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     <h2 class="title">
      <a name="innodb-parameters">
      </a>
      17.14 InnoDB Startup Options and System Variables
     </h2>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045159103408">
  </a>
  <a class="indexterm" name="idm46045159101984">
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  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a class="xref" href="innodb-parameters.html#innodb-parameters-startup" title="InnoDB Startup Options">
       InnoDB Startup Options
      </a>
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="xref" href="innodb-parameters.html#innodb-parameters-sysvars" title="InnoDB System Variables">
       InnoDB System Variables
      </a>
     </p>
    </li>
   </ul>
  </div>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      System variables that are true or false can be enabled at
          server startup by naming them, or disabled by using a
      <code class="literal">
       --skip-
      </code>
      prefix. For example, to enable or
          disable the
      <code class="literal">
       InnoDB
      </code>
      adaptive hash index, you
          can use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
       <code class="option">
        --innodb-adaptive-hash-index
       </code>
      </a>
      or
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
       <code class="option">
        --skip-innodb-adaptive-hash-index
       </code>
      </a>
      on the command line, or
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
       <code class="literal">
        innodb_adaptive_hash_index
       </code>
      </a>
      or
      <code class="literal">
       skip_innodb_adaptive_hash_index
      </code>
      in an
          option file.
     </p>
    </li>
    <li class="listitem">
     <p>
      Some variable descriptions refer to
      <span class="quote">
       “
       <span class="quote">
        enabling
       </span>
       ”
      </span>
      or
      <span class="quote">
       “
       <span class="quote">
        disabling
       </span>
       ”
      </span>
      a variable. These variables can be
          enabled with the
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
       </code>
      </a>
      statement by setting them to
      <code class="literal">
       ON
      </code>
      or
      <code class="literal">
       1
      </code>
      , or disabled by setting them to
      <code class="literal">
       OFF
      </code>
      or
      <code class="literal">
       0
      </code>
      . Boolean
          variables can be set at startup to the values
      <code class="literal">
       ON
      </code>
      ,
      <code class="literal">
       TRUE
      </code>
      ,
      <code class="literal">
       OFF
      </code>
      , and
      <code class="literal">
       FALSE
      </code>
      (not
          case-sensitive), as well as
      <code class="literal">
       1
      </code>
      and
      <code class="literal">
       0
      </code>
      . See
      <a class="xref" href="option-modifiers.html" title="6.2.2.4 Program Option Modifiers">
       Section 6.2.2.4, “Program Option Modifiers”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      System variables that take a numeric value can be specified as
      <code class="option">
       --
       <em class="replaceable">
        <code>
         var_name
        </code>
       </em>
       =
       <em class="replaceable">
        <code>
         value
        </code>
       </em>
      </code>
      on the command line or as
      <code class="literal">
       <em class="replaceable">
        <code>
         var_name
        </code>
       </em>
       =
       <em class="replaceable">
        <code>
         value
        </code>
       </em>
      </code>
      in option files.
     </p>
    </li>
    <li class="listitem">
     <p>
      Many system variables can be changed at runtime (see
      <a class="xref" href="dynamic-system-variables.html" title="7.1.9.2 Dynamic System Variables">
       Section 7.1.9.2, “Dynamic System Variables”
      </a>
      ).
     </p>
    </li>
    <li class="listitem">
     <p>
      For information about
      <code class="literal">
       GLOBAL
      </code>
      and
      <code class="literal">
       SESSION
      </code>
      variable scope modifiers, refer to
          the
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
       </code>
      </a>
      statement documentation.
     </p>
    </li>
    <li class="listitem">
     <p>
      Certain options control the locations and layout of the
      <code class="literal">
       InnoDB
      </code>
      data files.
      <a class="xref" href="innodb-init-startup-configuration.html" title="17.8.1 InnoDB Startup Configuration">
       Section 17.8.1, “InnoDB Startup Configuration”
      </a>
      explains
          how to use these options.
     </p>
    </li>
    <li class="listitem">
     <p>
      Some options, which you might not use initially, help tune
      <code class="literal">
       InnoDB
      </code>
      performance characteristics based on
          machine capacity and database
      <a class="link" href="glossary.html#glos_workload" title="workload">
       workload
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      For more information on specifying options and system
          variables, see
      <a class="xref" href="program-options.html" title="6.2.2 Specifying Program Options">
       Section 6.2.2, “Specifying Program Options”
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
  <div class="table">
   <a name="idm46045159065744">
   </a>
   <p class="title">
    <b>
     Table 17.23 InnoDB Option and Variable Reference
    </b>
   </p>
   <div class="table-contents">
    <table frame="box" rules="all" summary="Reference for InnoDB command-line options and system variables.">
     <colgroup>
      <col style="width: 20%"/>
      <col style="width: 15%"/>
      <col style="width: 15%"/>
      <col style="width: 15%"/>
      <col style="width: 15%"/>
      <col style="width: 15%"/>
      <col style="width: 15%"/>
     </colgroup>
     <thead>
      <tr>
       <th scope="col">
        Name
       </th>
       <th scope="col">
        Cmd-Line
       </th>
       <th scope="col">
        Option File
       </th>
       <th scope="col">
        System Var
       </th>
       <th scope="col">
        Status Var
       </th>
       <th scope="col">
        Var Scope
       </th>
       <th scope="col">
        Dynamic
       </th>
      </tr>
     </thead>
     <tbody>
      <tr>
       <th scope="row">
        <a class="link" href="server-system-variables.html#sysvar_foreign_key_checks">
         foreign_key_checks
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing">
         innodb_adaptive_flushing
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing_lwm">
         innodb_adaptive_flushing_lwm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
         innodb_adaptive_hash_index
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index_parts">
         innodb_adaptive_hash_index_parts
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_max_sleep_delay">
         innodb_adaptive_max_sleep_delay
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
         innodb_autoextend_increment
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_autoinc_lock_mode">
         innodb_autoinc_lock_mode
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_background_drop_list_empty">
         innodb_background_drop_list_empty
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_bytes_data">
         Innodb_buffer_pool_bytes_data
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_bytes_dirty">
         Innodb_buffer_pool_bytes_dirty
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
         innodb_buffer_pool_chunk_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_debug">
         innodb_buffer_pool_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
         innodb_buffer_pool_dump_at_shutdown
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
         innodb_buffer_pool_dump_now
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_pct">
         innodb_buffer_pool_dump_pct
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_dump_status">
         Innodb_buffer_pool_dump_status
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_filename">
         innodb_buffer_pool_filename
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_in_core_file">
         innodb_buffer_pool_in_core_file
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
         innodb_buffer_pool_instances
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_abort">
         innodb_buffer_pool_load_abort
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
         innodb_buffer_pool_load_at_startup
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
         innodb_buffer_pool_load_now
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_load_status">
         Innodb_buffer_pool_load_status
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_data">
         Innodb_buffer_pool_pages_data
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_dirty">
         Innodb_buffer_pool_pages_dirty
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_flushed">
         Innodb_buffer_pool_pages_flushed
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_free">
         Innodb_buffer_pool_pages_free
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_latched">
         Innodb_buffer_pool_pages_latched
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_misc">
         Innodb_buffer_pool_pages_misc
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_pages_total">
         Innodb_buffer_pool_pages_total
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_ahead">
         Innodb_buffer_pool_read_ahead
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_ahead_evicted">
         Innodb_buffer_pool_read_ahead_evicted
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_ahead_rnd">
         Innodb_buffer_pool_read_ahead_rnd
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_requests">
         Innodb_buffer_pool_read_requests
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_reads">
         Innodb_buffer_pool_reads
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status">
         Innodb_buffer_pool_resize_status
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
         innodb_buffer_pool_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_wait_free">
         Innodb_buffer_pool_wait_free
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_write_requests">
         Innodb_buffer_pool_write_requests
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffer_max_size">
         innodb_change_buffer_max_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering">
         innodb_change_buffering
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering_debug">
         innodb_change_buffering_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_checkpoint_disabled">
         innodb_checkpoint_disabled
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_checksum_algorithm">
         innodb_checksum_algorithm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_cmp_per_index_enabled">
         innodb_cmp_per_index_enabled
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_commit_concurrency">
         innodb_commit_concurrency
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_compress_debug">
         innodb_compress_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_failure_threshold_pct">
         innodb_compression_failure_threshold_pct
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_level">
         innodb_compression_level
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_pad_pct_max">
         innodb_compression_pad_pct_max
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
         innodb_concurrency_tickets
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
         innodb_data_file_path
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_fsyncs">
         Innodb_data_fsyncs
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
         innodb_data_home_dir
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_pending_fsyncs">
         Innodb_data_pending_fsyncs
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_pending_reads">
         Innodb_data_pending_reads
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_pending_writes">
         Innodb_data_pending_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_read">
         Innodb_data_read
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_reads">
         Innodb_data_reads
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_writes">
         Innodb_data_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_data_written">
         Innodb_data_written
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_dblwr_pages_written">
         Innodb_dblwr_pages_written
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_dblwr_writes">
         Innodb_dblwr_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_buffer_size">
         innodb_ddl_buffer_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Session
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_log_crash_reset_debug">
         innodb_ddl_log_crash_reset_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_threads">
         innodb_ddl_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Session
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_deadlock_detect">
         innodb_deadlock_detect
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
         innodb_dedicated_server
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
         innodb_default_row_format
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
         innodb_directories
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_disable_sort_file_cache">
         innodb_disable_sort_file_cache
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
         innodb_doublewrite
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_batch_size">
         innodb_doublewrite_batch_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_dir">
         innodb_doublewrite_dir
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_files">
         innodb_doublewrite_files
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_pages">
         innodb_doublewrite_pages
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_fast_shutdown">
         innodb_fast_shutdown
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
         innodb_fil_make_page_dirty_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
         innodb_file_per_table
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
         innodb_fill_factor
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
         innodb_flush_log_at_timeout
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
         innodb_flush_log_at_trx_commit
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
         innodb_flush_method
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_neighbors">
         innodb_flush_neighbors
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
         innodb_flush_sync
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_flushing_avg_loops">
         innodb_flushing_avg_loops
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_force_load_corrupted">
         innodb_force_load_corrupted
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
         innodb_force_recovery
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_fsync_threshold">
         innodb_fsync_threshold
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_aux_table">
         innodb_ft_aux_table
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_cache_size">
         innodb_ft_cache_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_diag_print">
         innodb_ft_enable_diag_print
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_stopword">
         innodb_ft_enable_stopword
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_max_token_size">
         innodb_ft_max_token_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_min_token_size">
         innodb_ft_min_token_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_num_word_optimize">
         innodb_ft_num_word_optimize
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_result_cache_limit">
         innodb_ft_result_cache_limit
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
         innodb_ft_server_stopword_table
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_sort_pll_degree">
         innodb_ft_sort_pll_degree
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_total_cache_size">
         innodb_ft_total_cache_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
         innodb_ft_user_stopword_table
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_have_atomic_builtins">
         Innodb_have_atomic_builtins
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_idle_flush_pct">
         innodb_idle_flush_pct
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
         innodb_io_capacity
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
         innodb_io_capacity_max
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_limit_optimistic_insert_debug">
         innodb_limit_optimistic_insert_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
         innodb_lock_wait_timeout
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_buffer_size">
         innodb_log_buffer_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_fuzzy_now">
         innodb_log_checkpoint_fuzzy_now
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_now">
         innodb_log_checkpoint_now
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checksums">
         innodb_log_checksums
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
         innodb_log_compressed_pages
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
         innodb_log_file_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
         innodb_log_files_in_group
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_group_home_dir">
         innodb_log_group_home_dir
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_abs_lwm">
         innodb_log_spin_cpu_abs_lwm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_pct_hwm">
         innodb_log_spin_cpu_pct_hwm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_wait_for_flush_spin_hwm">
         innodb_log_wait_for_flush_spin_hwm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_log_waits">
         Innodb_log_waits
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
         innodb_log_write_ahead_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_log_write_requests">
         Innodb_log_write_requests
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_log_writer_threads">
         innodb_log_writer_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_log_writes">
         Innodb_log_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
         innodb_lru_scan_depth
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct">
         innodb_max_dirty_pages_pct
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct_lwm">
         innodb_max_dirty_pages_pct_lwm
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag">
         innodb_max_purge_lag
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag_delay">
         innodb_max_purge_lag_delay
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_max_undo_log_size">
         innodb_max_undo_log_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_merge_threshold_set_all_debug">
         innodb_merge_threshold_set_all_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_disable">
         innodb_monitor_disable
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_enable">
         innodb_monitor_enable
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset">
         innodb_monitor_reset
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset_all">
         innodb_monitor_reset_all
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_num_open_files">
         Innodb_num_open_files
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_numa_interleave">
         innodb_numa_interleave
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_pct">
         innodb_old_blocks_pct
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_time">
         innodb_old_blocks_time
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_online_alter_log_max_size">
         innodb_online_alter_log_max_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
         innodb_open_files
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_optimize_fulltext_only">
         innodb_optimize_fulltext_only
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_os_log_fsyncs">
         Innodb_os_log_fsyncs
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_os_log_pending_fsyncs">
         Innodb_os_log_pending_fsyncs
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_os_log_pending_writes">
         Innodb_os_log_pending_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_os_log_written">
         Innodb_os_log_written
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_page_cleaners">
         innodb_page_cleaners
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_page_size">
         Innodb_page_size
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
         innodb_page_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_pages_created">
         Innodb_pages_created
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_pages_read">
         Innodb_pages_read
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_pages_written">
         Innodb_pages_written
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_parallel_read_threads">
         innodb_parallel_read_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Session
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_print_all_deadlocks">
         innodb_print_all_deadlocks
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_print_ddl_logs">
         innodb_print_ddl_logs
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
         innodb_purge_batch_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_rseg_truncate_frequency">
         innodb_purge_rseg_truncate_frequency
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_threads">
         innodb_purge_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_random_read_ahead">
         innodb_random_read_ahead
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_read_ahead_threshold">
         innodb_read_ahead_threshold
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
         innodb_read_io_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
         innodb_read_only
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_archive_dirs">
         innodb_redo_log_archive_dirs
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
         innodb_redo_log_capacity
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_capacity_resized">
         Innodb_redo_log_capacity_resized
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_checkpoint_lsn">
         Innodb_redo_log_checkpoint_lsn
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_current_lsn">
         Innodb_redo_log_current_lsn
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_enabled">
         Innodb_redo_log_enabled
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_encrypt">
         innodb_redo_log_encrypt
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_flushed_to_disk_lsn">
         Innodb_redo_log_flushed_to_disk_lsn
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_logical_size">
         Innodb_redo_log_logical_size
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_physical_size">
         Innodb_redo_log_physical_size
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_read_only">
         Innodb_redo_log_read_only
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_resize_status">
         Innodb_redo_log_resize_status
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_uuid">
         Innodb_redo_log_uuid
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_replication_delay">
         innodb_replication_delay
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_on_timeout">
         innodb_rollback_on_timeout
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_segments">
         innodb_rollback_segments
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_row_lock_current_waits">
         Innodb_row_lock_current_waits
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_row_lock_time">
         Innodb_row_lock_time
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_row_lock_time_avg">
         Innodb_row_lock_time_avg
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_row_lock_time_max">
         Innodb_row_lock_time_max
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_row_lock_waits">
         Innodb_row_lock_waits
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_rows_deleted">
         Innodb_rows_deleted
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_rows_inserted">
         Innodb_rows_inserted
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_rows_read">
         Innodb_rows_read
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_rows_updated">
         Innodb_rows_updated
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
         innodb_saved_page_number_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_segment_reserve_factor">
         innodb_segment_reserve_factor
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_sort_buffer_size">
         innodb_sort_buffer_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_delay">
         innodb_spin_wait_delay
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_pause_multiplier">
         innodb_spin_wait_pause_multiplier
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_auto_recalc">
         innodb_stats_auto_recalc
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
         innodb_stats_include_delete_marked
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_method">
         innodb_stats_method
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_on_metadata">
         innodb_stats_on_metadata
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
         innodb_stats_persistent
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
         innodb_stats_persistent_sample_pages
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
         innodb_stats_transient_sample_pages
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#option_mysqld_innodb-status-file">
         innodb-status-file
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output">
         innodb_status_output
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output_locks">
         innodb_status_output_locks
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
         innodb_strict_mode
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_array_size">
         innodb_sync_array_size
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_debug">
         innodb_sync_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_spin_loops">
         innodb_sync_spin_loops
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_system_rows_deleted">
         Innodb_system_rows_deleted
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_system_rows_inserted">
         Innodb_system_rows_inserted
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_system_rows_read">
         Innodb_system_rows_read
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_system_rows_updated">
         Innodb_system_rows_updated
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_table_locks">
         innodb_table_locks
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
         innodb_temp_data_file_path
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_tablespaces_dir">
         innodb_temp_tablespaces_dir
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
         innodb_thread_concurrency
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
         innodb_thread_sleep_delay
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
         innodb_tmpdir
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_truncated_status_writes">
         Innodb_truncated_status_writes
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_purge_view_update_only_debug">
         innodb_trx_purge_view_update_only_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_rseg_n_slots_debug">
         innodb_trx_rseg_n_slots_debug
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
         innodb_undo_directory
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_encrypt">
         innodb_undo_log_encrypt
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_truncate">
         innodb_undo_log_truncate
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_tablespaces">
         innodb_undo_tablespaces
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_undo_tablespaces_active">
         Innodb_undo_tablespaces_active
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_undo_tablespaces_explicit">
         Innodb_undo_tablespaces_explicit
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_undo_tablespaces_implicit">
         Innodb_undo_tablespaces_implicit
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-status-variables.html#statvar_Innodb_undo_tablespaces_total">
         Innodb_undo_tablespaces_total
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
         innodb_use_fdatasync
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_use_native_aio">
         innodb_use_native_aio
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_validate_tablespace_paths">
         innodb_validate_tablespace_paths
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_version">
         innodb_version
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
         innodb_write_io_threads
        </a>
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Global
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        <a class="link" href="server-system-variables.html#sysvar_unique_checks">
         unique_checks
        </a>
       </th>
       <td>
       </td>
       <td>
       </td>
       <td>
        Yes
       </td>
       <td>
       </td>
       <td>
        Both
       </td>
       <td>
        Yes
       </td>
      </tr>
     </tbody>
    </table>
   </div>
   <div class="table-contents">
    <table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
     <thead>
      <tr>
       <th scope="col" style="width: 312.094px;">
        Name
       </th>
       <th scope="col" style="width: 64.875px;">
        Cmd-Line
       </th>
       <th scope="col" style="width: 73.3594px;">
        Option File
       </th>
       <th scope="col" style="width: 75.0938px;">
        System Var
       </th>
       <th scope="col" style="width: 70.75px;">
        Status Var
       </th>
       <th scope="col" style="width: 72.5156px;">
        Var Scope
       </th>
       <th scope="col" style="width: 69.3125px;">
        Dynamic
       </th>
      </tr>
     </thead>
    </table>
   </div>
  </div>
  <br class="table-break"/>
  <h3>
   <a name="innodb-parameters-startup">
   </a>
   InnoDB Startup Options
  </h3>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a name="option_mysqld_innodb-dedicated-server">
      </a>
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
       <code class="option">
        --innodb-dedicated-server
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157426144">
     </a>
     <a class="indexterm" name="idm46045157424640">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb-dedicated-server">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-dedicated-server[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           innodb_dedicated_server
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      When this option is set by starting the server with
      <code class="option">
       --innodb-dedicated-server
      </code>
      or
      <code class="option">
       --innodb-dedicated-server=ON
      </code>
      , either on the
          command line or in a
      <code class="filename">
       my.cnf
      </code>
      file,
      <code class="literal">
       InnoDB
      </code>
      automatically calculates and sets
          the values of the following variables:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
          <code class="literal">
           innodb_buffer_pool_size
          </code>
         </a>
        </p>
       </li>
       <li class="listitem">
        <p>
         <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
          <code class="literal">
           innodb_redo_log_capacity
          </code>
         </a>
        </p>
       </li>
      </ul>
     </div>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       In older versions of MySQL 8.0,
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
        <code class="literal">
         innodb_log_file_size
        </code>
       </a>
       and
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
        <code class="literal">
         innodb_log_files_in_group
        </code>
       </a>
       were also set by
       <code class="option">
        --innodb-dedicated-server
       </code>
       .
       <code class="literal">
        innodb_log_file_size
       </code>
       and
       <code class="literal">
        innodb_log_files_in_group
       </code>
       have since been
            deprecated, and superseded by
       <code class="literal">
        innodb_redo_log_capacity
       </code>
       . See
       <a class="xref" href="innodb-redo-log.html" title="17.6.5 Redo Log">
        Section 17.6.5, “Redo Log”
       </a>
       .
      </p>
      <p>
       In MySQL 8.0,
       <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
        <code class="literal">
         innodb_flush_method
        </code>
       </a>
       was
            also set automatically by this option, but in MySQL 8.4,
            this is no longer the case.
      </p>
     </div>
     <p>
      You should consider using
      <code class="option">
       --innodb-dedicated-server
      </code>
      only if the MySQL
          instance resides on a dedicated server where it can use all
          available system resources. Using this option is not
          recommended if the MySQL instance shares system resources with
          other applications.
     </p>
     <p>
      It is strongly recommended that you read
      <a class="xref" href="innodb-dedicated-server.html" title="17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server">
       Section 17.8.12, “Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server”
      </a>
      , before using this
          option in production.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="option_mysqld_innodb-status-file">
      </a>
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-status-file">
       <code class="option">
        --innodb-status-file
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157383008">
     </a>
     <a class="indexterm" name="idm46045157381552">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb-status-file">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-status-file[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <code class="option">
       --innodb-status-file
      </code>
      startup option
          controls whether
      <code class="literal">
       InnoDB
      </code>
      creates a file
          named
      <code class="filename">
       innodb_status.
       <em class="replaceable">
        <code>
         pid
        </code>
       </em>
      </code>
      in the data directory and writes
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB STATUS
       </code>
      </a>
      output to it every 15 seconds,
          approximately.
     </p>
     <p>
      The
      <code class="filename">
       innodb_status.
       <em class="replaceable">
        <code>
         pid
        </code>
       </em>
      </code>
      file is not created by default. To create it, start
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      with the
      <code class="option">
       --innodb-status-file
      </code>
      option.
      <code class="literal">
       InnoDB
      </code>
      removes the file when the server is
          shut down normally. If an abnormal shutdown occurs, the status
          file may have to be removed manually.
     </p>
     <p>
      The
      <code class="option">
       --innodb-status-file
      </code>
      option is intended
          for temporary use, as
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB STATUS
       </code>
      </a>
      output generation can affect
          performance, and the
      <code class="filename">
       innodb_status.
       <em class="replaceable">
        <code>
         pid
        </code>
       </em>
      </code>
      file can become quite large over time.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-enabling-monitors.html" title="17.17.2 Enabling InnoDB Monitors">
       Section 17.17.2, “Enabling InnoDB Monitors”
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
  <h3>
   <a name="innodb-parameters-sysvars">
   </a>
   InnoDB System Variables
  </h3>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_adaptive_flushing">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing">
       <code class="literal">
        innodb_adaptive_flushing
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157353568">
     </a>
     <a class="indexterm" name="idm46045157352464">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_adaptive_flushing">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-adaptive-flushing[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing">
            innodb_adaptive_flushing
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <a class="indexterm" name="idm46045157330800">
     </a>
     <p>
      Specifies whether to dynamically adjust the rate of flushing
      <a class="link" href="glossary.html#glos_dirty_page" title="dirty page">
       dirty pages
      </a>
      in the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      based on
          the workload. Adjusting the flush rate dynamically is intended
          to avoid bursts of I/O activity. This setting is enabled by
          default. See
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      for
          more information. For general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_adaptive_flushing_lwm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing_lwm">
       <code class="literal">
        innodb_adaptive_flushing_lwm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157322784">
     </a>
     <a class="indexterm" name="idm46045157321680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_adaptive_flushing_lwm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-adaptive-flushing-lwm=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_flushing_lwm">
            innodb_adaptive_flushing_lwm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           10
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           70
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the low water mark representing percentage of
      <a class="link" href="glossary.html#glos_redo_log" title="redo log">
       redo log
      </a>
      capacity at
          which
      <a class="link" href="glossary.html#glos_adaptive_flushing" title="adaptive flushing">
       adaptive
          flushing
      </a>
      is enabled. For more information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_adaptive_hash_index">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
       <code class="literal">
        innodb_adaptive_hash_index
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157289600">
     </a>
     <a class="indexterm" name="idm46045157288496">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_adaptive_hash_index">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-adaptive-hash-index[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
            innodb_adaptive_hash_index
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Whether the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_adaptive_hash_index" title="adaptive hash index">
       adaptive hash
          index
      </a>
      is enabled or disabled. It may be desirable,
          depending on your workload, to dynamically enable or disable
      <a class="link" href="glossary.html#glos_adaptive_hash_index" title="adaptive hash index">
       adaptive hash
          indexing
      </a>
      to improve query performance. Because the
          adaptive hash index may not be useful for all workloads,
          conduct benchmarks with it both enabled and disabled, using
          realistic workloads. See
      <a class="xref" href="innodb-adaptive-hash.html" title="17.5.3 Adaptive Hash Index">
       Section 17.5.3, “Adaptive Hash Index”
      </a>
      for details.
     </p>
     <p>
      This variable is disabled by default. You can modify this
          parameter using the
      <code class="literal">
       SET GLOBAL
      </code>
      statement,
          without restarting the server. Changing the setting at runtime
          requires privileges sufficient to set global system variables.
          See
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      . You can also
          use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index">
       <code class="option">
        --innodb-adaptive-hash-index
       </code>
      </a>
      at
          server startup to enable it.
     </p>
     <p>
      Disabling the adaptive hash index empties the hash table
          immediately. Normal operations can continue while the hash
          table is emptied, and executing queries that were using the
          hash table access the index B-trees directly instead. When the
          adaptive hash index is re-enabled, the hash table is populated
          again during normal operation.
     </p>
     <p>
      Before MySQL 8.4, this option was enabled by default.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_adaptive_hash_index_parts">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index_parts">
       <code class="literal">
        innodb_adaptive_hash_index_parts
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157256064">
     </a>
     <a class="indexterm" name="idm46045157254960">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_adaptive_hash_index_parts">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-adaptive-hash-index-parts=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_hash_index_parts">
            innodb_adaptive_hash_index_parts
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Numeric
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           8
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           512
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Partitions the adaptive hash index search system. Each index
          is bound to a specific partition, with each partition
          protected by a separate latch.
     </p>
     <p>
      The adaptive hash index search system is partitioned into 8
          parts by default. The maximum setting is 512.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-adaptive-hash.html" title="17.5.3 Adaptive Hash Index">
       Section 17.5.3, “Adaptive Hash Index”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_adaptive_max_sleep_delay">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_max_sleep_delay">
       <code class="literal">
        innodb_adaptive_max_sleep_delay
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157223728">
     </a>
     <a class="indexterm" name="idm46045157222624">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_adaptive_max_sleep_delay">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-adaptive-max-sleep-delay=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_max_sleep_delay">
            innodb_adaptive_max_sleep_delay
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           150000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          microseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Permits
      <code class="literal">
       InnoDB
      </code>
      to automatically adjust the
          value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
       <code class="literal">
        innodb_thread_sleep_delay
       </code>
      </a>
      up
          or down according to the current workload. Any nonzero value
          enables automated, dynamic adjustment of the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
       <code class="literal">
        innodb_thread_sleep_delay
       </code>
      </a>
      value, up to the maximum value specified in the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_max_sleep_delay">
       <code class="literal">
        innodb_adaptive_max_sleep_delay
       </code>
      </a>
      option. The value represents the number of microseconds. This
          option can be useful in busy systems, with greater than 16
      <code class="literal">
       InnoDB
      </code>
      threads. (In practice, it is most
          valuable for MySQL systems with hundreds or thousands of
          simultaneous connections.)
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-thread_concurrency.html" title="17.8.4 Configuring Thread Concurrency for InnoDB">
       Section 17.8.4, “Configuring Thread Concurrency for InnoDB”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_autoextend_increment">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
       <code class="literal">
        innodb_autoextend_increment
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157184176">
     </a>
     <a class="indexterm" name="idm46045157183072">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_autoextend_increment">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-autoextend-increment=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
            innodb_autoextend_increment
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          megabytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The increment size (in megabytes) for extending the size of an
          auto-extending
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_system_tablespace" title="system tablespace">
       system
          tablespace
      </a>
      file when it becomes full. The default value
          is 64. For related information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-data-file-configuration" title="System Tablespace Data File Configuration">
       System Tablespace Data File Configuration
      </a>
      , and
      <a class="xref" href="innodb-system-tablespace.html#innodb-resize-system-tablespace" title="Resizing the System Tablespace">
       Resizing the System Tablespace
      </a>
      .
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
       <code class="literal">
        innodb_autoextend_increment
       </code>
      </a>
      setting does not affect
      <a class="link" href="glossary.html#glos_file_per_table" title="file-per-table">
       file-per-table
      </a>
      tablespace files or
      <a class="link" href="glossary.html#glos_general_tablespace" title="general tablespace">
       general
          tablespace
      </a>
      files. These files are auto-extending
          regardless of the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
       <code class="literal">
        innodb_autoextend_increment
       </code>
      </a>
      setting. The initial extensions are by small amounts, after
          which extensions occur in increments of 4MB.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_autoinc_lock_mode">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_autoinc_lock_mode">
       <code class="literal">
        innodb_autoinc_lock_mode
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157143568">
     </a>
     <a class="indexterm" name="idm46045157142464">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_autoinc_lock_mode">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-autoinc-lock-mode=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_autoinc_lock_mode">
            innodb_autoinc_lock_mode
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            0
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            1
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            2
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="glossary.html#glos_lock_mode" title="lock mode">
       lock mode
      </a>
      to use for
          generating
      <a class="link" href="glossary.html#glos_auto_increment" title="auto-increment">
       auto-increment
      </a>
      values. Permissible values are 0, 1, or 2, for traditional,
          consecutive, or interleaved, respectively.
     </p>
     <p>
      The default setting is 2 (interleaved), for compatibility with
          row-based replication.
     </p>
     <p>
      For the characteristics of each lock mode, see
      <a class="xref" href="innodb-auto-increment-handling.html#innodb-auto-increment-lock-modes" title="InnoDB AUTO_INCREMENT Lock Modes">
       InnoDB AUTO_INCREMENT Lock Modes
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_background_drop_list_empty">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_background_drop_list_empty">
       <code class="literal">
        innodb_background_drop_list_empty
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157109440">
     </a>
     <a class="indexterm" name="idm46045157108400">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_background_drop_list_empty">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-background-drop-list-empty[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_background_drop_list_empty">
            innodb_background_drop_list_empty
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enabling the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_background_drop_list_empty">
       <code class="literal">
        innodb_background_drop_list_empty
       </code>
      </a>
      debug option helps avoid test case failures by delaying table
          creation until the background drop list is empty. For example,
          if test case A places table
      <code class="literal">
       t1
      </code>
      on the
          background drop list, test case B waits until the background
          drop list is empty before creating table
      <code class="literal">
       t1
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_chunk_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157080768">
     </a>
     <a class="indexterm" name="idm46045157079664">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_chunk_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-chunk-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
            innodb_buffer_pool_chunk_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           134217728
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1048576
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           innodb_buffer_pool_size / innodb_buffer_pool_instances
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      defines the chunk size for
      <code class="literal">
       InnoDB
      </code>
      buffer
          pool resizing operations.
     </p>
     <p>
      To avoid copying all buffer pool pages during resizing
          operations, the operation is performed in
      <span class="quote">
       “
       <span class="quote">
        chunks
       </span>
       ”
      </span>
      . By default,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      is 128MB (134217728 bytes). The number of pages contained in a
          chunk depends on the value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      .
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      can be increased or decreased in units of 1MB (1048576 bytes).
     </p>
     <p>
      The following conditions apply when altering the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      value:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         If
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         *
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
          <code class="literal">
           innodb_buffer_pool_instances
          </code>
         </a>
         is larger than the current buffer pool size when the
              buffer pool is initialized,
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         is truncated to
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
          <code class="literal">
           innodb_buffer_pool_size
          </code>
         </a>
         /
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
          <code class="literal">
           innodb_buffer_pool_instances
          </code>
         </a>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         Buffer pool size must always be equal to or a multiple of
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         *
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
          <code class="literal">
           innodb_buffer_pool_instances
          </code>
         </a>
         .
              If you alter
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         ,
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
          <code class="literal">
           innodb_buffer_pool_size
          </code>
         </a>
         is automatically rounded to a value that is equal to or a
              multiple of
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         *
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
          <code class="literal">
           innodb_buffer_pool_instances
          </code>
         </a>
         .
              The adjustment occurs when the buffer pool is initialized.
        </p>
       </li>
      </ul>
     </div>
     <div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Important
      </div>
      <p>
       Care should be taken when changing
       <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
        <code class="literal">
         innodb_buffer_pool_chunk_size
        </code>
       </a>
       ,
            as changing this value can automatically increase the size
            of the buffer pool. Before changing
       <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
        <code class="literal">
         innodb_buffer_pool_chunk_size
        </code>
       </a>
       ,
            calculate its effect on
       <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
        <code class="literal">
         innodb_buffer_pool_size
        </code>
       </a>
       to
            ensure that the resulting buffer pool size is acceptable.
      </p>
     </div>
     <p>
      To avoid potential performance issues, the number of chunks
          (
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      /
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      )
          should not exceed 1000.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      variable is dynamic, which permits resizing the buffer pool
          while the server is online. However, the buffer pool size must
          be equal to or a multiple of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      ,
          and changing either of those variable settings requires
          restarting the server.
     </p>
     <p>
      See
      <a class="xref" href="innodb-buffer-pool-resize.html" title="17.8.3.1 Configuring InnoDB Buffer Pool Size">
       Section 17.8.3.1, “Configuring InnoDB Buffer Pool Size”
      </a>
      for more
          information.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_debug">
       <code class="literal">
        innodb_buffer_pool_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045157009264">
     </a>
     <a class="indexterm" name="idm46045157008176">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-debug[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_debug">
            innodb_buffer_pool_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enabling this option permits multiple buffer pool instances
          when the buffer pool is less than 1GB in size, ignoring the
          1GB minimum buffer pool size constraint imposed on
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      .
          The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_debug">
       <code class="literal">
        innodb_buffer_pool_debug
       </code>
      </a>
      option is only available if debugging support is compiled in
          using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_dump_at_shutdown">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
       <code class="literal">
        innodb_buffer_pool_dump_at_shutdown
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156979072">
     </a>
     <a class="indexterm" name="idm46045156978032">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_dump_at_shutdown">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-dump-at-shutdown[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
            innodb_buffer_pool_dump_at_shutdown
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies whether to record the pages cached in the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      when the
          MySQL server is shut down, to shorten the
      <a class="link" href="glossary.html#glos_warm_up" title="warm up">
       warmup
      </a>
      process at the next
          restart. Typically used in combination with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
       <code class="literal">
        innodb_buffer_pool_load_at_startup
       </code>
      </a>
      .
          The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_pct">
       <code class="literal">
        innodb_buffer_pool_dump_pct
       </code>
      </a>
      option defines the percentage of most recently used buffer
          pool pages to dump.
     </p>
     <p>
      Both
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
       <code class="literal">
        innodb_buffer_pool_dump_at_shutdown
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
       <code class="literal">
        innodb_buffer_pool_load_at_startup
       </code>
      </a>
      are enabled by default.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_dump_now">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
       <code class="literal">
        innodb_buffer_pool_dump_now
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156943904">
     </a>
     <a class="indexterm" name="idm46045156942800">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_dump_now">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-dump-now[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
            innodb_buffer_pool_dump_now
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Immediately makes a record of pages cached in the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      . Typically
          used in combination with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
       <code class="literal">
        innodb_buffer_pool_load_now
       </code>
      </a>
      .
     </p>
     <p>
      Enabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
       <code class="literal">
        innodb_buffer_pool_dump_now
       </code>
      </a>
      triggers the recording action but does not alter the variable
          setting, which always remains
      <code class="literal">
       OFF
      </code>
      or
      <code class="literal">
       0
      </code>
      . To view buffer pool dump status after
          triggering a dump, query the
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_dump_status">
       <code class="literal">
        Innodb_buffer_pool_dump_status
       </code>
      </a>
      variable.
     </p>
     <p>
      Enabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
       <code class="literal">
        innodb_buffer_pool_dump_now
       </code>
      </a>
      triggers the dump action but does not alter the variable
          setting, which always remains
      <code class="literal">
       OFF
      </code>
      or
      <code class="literal">
       0
      </code>
      . To view buffer pool dump status after
          triggering a dump, query the
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_dump_status">
       <code class="literal">
        Innodb_buffer_pool_dump_status
       </code>
      </a>
      variable.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_dump_pct">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_pct">
       <code class="literal">
        innodb_buffer_pool_dump_pct
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156905040">
     </a>
     <a class="indexterm" name="idm46045156903936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_dump_pct">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-dump-pct=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_pct">
            innodb_buffer_pool_dump_pct
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           25
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the percentage of the most recently used pages for
          each buffer pool to read out and dump. The range is 1 to 100.
          The default value is 25. For example, if there are 4 buffer
          pools with 100 pages each, and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_pct">
       <code class="literal">
        innodb_buffer_pool_dump_pct
       </code>
      </a>
      is set to 25, the 25 most recently used pages from each buffer
          pool are dumped.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_filename">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_filename">
       <code class="literal">
        innodb_buffer_pool_filename
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156872896">
     </a>
     <a class="indexterm" name="idm46045156871792">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_filename">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-filename=file_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_filename">
            innodb_buffer_pool_filename
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          File name
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ib_buffer_pool
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the name of the file that holds the list of
          tablespace IDs and page IDs produced by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
       <code class="literal">
        innodb_buffer_pool_dump_at_shutdown
       </code>
      </a>
      or
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_now">
       <code class="literal">
        innodb_buffer_pool_dump_now
       </code>
      </a>
      .
          Tablespace IDs and page IDs are saved in the following format:
      <code class="literal">
       space, page_id
      </code>
      . By default, the file is
          named
      <code class="filename">
       ib_buffer_pool
      </code>
      and is located in
          the
      <code class="literal">
       InnoDB
      </code>
      data directory. A non-default
          location must be specified relative to the data directory.
     </p>
     <p>
      A file name can be specified at runtime, using a
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
       </code>
      </a>
      statement:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa45697009"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> innodb_buffer_pool_filename<span class="token operator">=</span><span class="token string"><em class="replaceable">'file_name'</em></span><span class="token punctuation">;</span></code></pre>
     </div>
     <p>
      You can also specify a file name at startup, in a startup
          string or MySQL configuration file. When specifying a file
          name at startup, the file must exist or
      <code class="literal">
       InnoDB
      </code>
      returns a startup error indicating
          that there is no such file or directory.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_in_core_file">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_in_core_file">
       <code class="literal">
        innodb_buffer_pool_in_core_file
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156836512">
     </a>
     <a class="indexterm" name="idm46045156835408">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_in_core_file">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-in-core-file[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_in_core_file">
            innodb_buffer_pool_in_core_file
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Disabling (default) the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_in_core_file">
       <code class="literal">
        innodb_buffer_pool_in_core_file
       </code>
      </a>
      variable reduces the size of core files by excluding
      <code class="literal">
       InnoDB
      </code>
      buffer pool pages.
     </p>
     <p>
      To use this variable, the
      <a class="link" href="server-system-variables.html#sysvar_core_file">
       <code class="literal">
        core_file
       </code>
      </a>
      variable must be
          enabled, and to disable this option the operating system must
          support the
      <code class="literal">
       MADV_DONTDUMP
      </code>
      non-POSIX
          extension to
      <code class="literal">
       madvise()
      </code>
      , which is supported
          in Linux 3.4 and later. For more information, see
      <a class="xref" href="innodb-buffer-pool-in-core-file.html" title="17.8.3.7 Excluding or Including Buffer Pool Pages from Core Files">
       Section 17.8.3.7, “Excluding or Including Buffer Pool Pages from Core Files”
      </a>
      .
     </p>
     <p>
      This is disabled by default on systems that support
      <code class="literal">
       MADV_DONTDUMP
      </code>
      , which is typically only
          Linux and not macOS or Windows.
     </p>
     <p>
      Before MySQL 8.4, this option was enabled by default.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_instances">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156802944">
     </a>
     <a class="indexterm" name="idm46045156801840">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_instances">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-instances=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
            innodb_buffer_pool_instances
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           see description
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of regions that the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      is divided
          into. For systems with buffer pools in the multi-gigabyte
          range, dividing the buffer pool into separate instances can
          improve concurrency, by reducing contention as different
          threads read and write to cached pages. Each page that is
          stored in or read from the buffer pool is assigned to one of
          the buffer pool instances randomly, using a hashing function.
          Each buffer pool manages its own free lists,
      <a class="link" href="glossary.html#glos_flush_list" title="flush list">
       flush lists
      </a>
      ,
      <a class="link" href="glossary.html#glos_lru" title="LRU">
       LRUs
      </a>
      , and all other data
          structures connected to a buffer pool, and is protected by its
          own buffer pool
      <a class="link" href="glossary.html#glos_mutex" title="mutex">
       mutex
      </a>
      .
     </p>
     <p>
      The total buffer pool size is divided among all the buffer
          pools. For best efficiency, specify a combination of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      so that each buffer pool instance is at least 1GB.
     </p>
     <p>
      If
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      &lt;= 1 GiB, then the default
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      value is 1.
     </p>
     <p>
      If
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      &gt; 1 GiB, then the default
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      value is the minimum value from the following two calculated
          hints, within a range of 1-64:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         Buffer pool hint: calculated as 1/2 of
              (
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
          <code class="literal">
           innodb_buffer_pool_size
          </code>
         </a>
         /
         <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
          <code class="literal">
           innodb_buffer_pool_chunk_size
          </code>
         </a>
         )
        </p>
       </li>
       <li class="listitem">
        <p>
         CPU hint: calculated as 1/4 of available logical
              processors
        </p>
       </li>
      </ul>
     </div>
     <p>
      For related information, see
      <a class="xref" href="innodb-buffer-pool-resize.html" title="17.8.3.1 Configuring InnoDB Buffer Pool Size">
       Section 17.8.3.1, “Configuring InnoDB Buffer Pool Size”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_load_abort">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_abort">
       <code class="literal">
        innodb_buffer_pool_load_abort
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156752416">
     </a>
     <a class="indexterm" name="idm46045156751312">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_load_abort">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-load-abort[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_abort">
            innodb_buffer_pool_load_abort
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Interrupts the process of restoring
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      contents
          triggered by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
       <code class="literal">
        innodb_buffer_pool_load_at_startup
       </code>
      </a>
      or
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
       <code class="literal">
        innodb_buffer_pool_load_now
       </code>
      </a>
      .
     </p>
     <p>
      Enabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_abort">
       <code class="literal">
        innodb_buffer_pool_load_abort
       </code>
      </a>
      triggers the abort action but does not alter the variable
          setting, which always remains
      <code class="literal">
       OFF
      </code>
      or
      <code class="literal">
       0
      </code>
      . To view buffer pool load status after
          triggering an abort action, query the
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_load_status">
       <code class="literal">
        Innodb_buffer_pool_load_status
       </code>
      </a>
      variable.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_load_at_startup">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
       <code class="literal">
        innodb_buffer_pool_load_at_startup
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156716688">
     </a>
     <a class="indexterm" name="idm46045156715648">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_load_at_startup">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-load-at-startup[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
            innodb_buffer_pool_load_at_startup
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies that, on MySQL server startup, the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      is
          automatically
      <a class="link" href="glossary.html#glos_warm_up" title="warm up">
       warmed up
      </a>
      by
          loading the same pages it held at an earlier time. Typically
          used in combination with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
       <code class="literal">
        innodb_buffer_pool_dump_at_shutdown
       </code>
      </a>
      .
     </p>
     <p>
      Both
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_dump_at_shutdown">
       <code class="literal">
        innodb_buffer_pool_dump_at_shutdown
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_at_startup">
       <code class="literal">
        innodb_buffer_pool_load_at_startup
       </code>
      </a>
      are enabled by default.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_load_now">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
       <code class="literal">
        innodb_buffer_pool_load_now
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156682928">
     </a>
     <a class="indexterm" name="idm46045156681824">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_load_now">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-load-now[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
            innodb_buffer_pool_load_now
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Immediately
      <a class="link" href="glossary.html#glos_warm_up" title="warm up">
       warms up
      </a>
      the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      by loading
          data pages without waiting for a server restart. Can be useful
          to bring cache memory back to a known state during
          benchmarking or to ready the MySQL server to resume its normal
          workload after running queries for reports or maintenance.
     </p>
     <p>
      Enabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_load_now">
       <code class="literal">
        innodb_buffer_pool_load_now
       </code>
      </a>
      triggers the load action but does not alter the variable
          setting, which always remains
      <code class="literal">
       OFF
      </code>
      or
      <code class="literal">
       0
      </code>
      . To view buffer pool load progress after
          triggering a load, query the
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_load_status">
       <code class="literal">
        Innodb_buffer_pool_load_status
       </code>
      </a>
      variable.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
       Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_buffer_pool_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156648848">
     </a>
     <a class="indexterm" name="idm46045156647808">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_buffer_pool_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-buffer-pool-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
            innodb_buffer_pool_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           134217728
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           5242880
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value (64-bit platforms)
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value (32-bit platforms)
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The size in bytes of the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      , the
          memory area where
      <code class="literal">
       InnoDB
      </code>
      caches table and
          index data. The default value is 134217728 bytes (128MB). The
          maximum value depends on the CPU architecture; the maximum is
          4294967295 (2
      <sup>
       32
      </sup>
      -1) on 32-bit
          systems and 18446744073709551615
          (2
      <sup>
       64
      </sup>
      -1) on 64-bit systems. On
          32-bit systems, the CPU architecture and operating system may
          impose a lower practical maximum size than the stated maximum.
          When the size of the buffer pool is greater than 1GB, setting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      to a value greater than 1 can improve the scalability on a
          busy server.
     </p>
     <p>
      A larger buffer pool requires less disk I/O to access the same
          table data more than once. On a dedicated database server, you
          might set the buffer pool size to 80% of the machine's
          physical memory size. Be aware of the following potential
          issues when configuring buffer pool size, and be prepared to
          scale back the size of the buffer pool if necessary.
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         Competition for physical memory can cause paging in the
              operating system.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          InnoDB
         </code>
         reserves additional memory for
              buffers and control structures, so that the total
              allocated space is approximately 10% greater than the
              specified buffer pool size.
        </p>
       </li>
       <li class="listitem">
        <p>
         Address space for the buffer pool must be contiguous,
              which can be an issue on Windows systems with DLLs that
              load at specific addresses.
        </p>
       </li>
       <li class="listitem">
        <p>
         The time to initialize the buffer pool is roughly
              proportional to its size. On instances with large buffer
              pools, initialization time might be significant. To reduce
              the initialization period, you can save the buffer pool
              state at server shutdown and restore it at server startup.
              See
         <a class="xref" href="innodb-preload-buffer-pool.html" title="17.8.3.6 Saving and Restoring the Buffer Pool State">
          Section 17.8.3.6, “Saving and Restoring the Buffer Pool State”
         </a>
         .
        </p>
       </li>
      </ul>
     </div>
     <p>
      When you increase or decrease buffer pool size, the operation
          is performed in chunks. Chunk size is defined by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      variable, which has a default of 128 MB.
     </p>
     <p>
      Buffer pool size must always be equal to or a multiple of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      .
          If you alter the buffer pool size to a value that is not equal
          to or a multiple of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      ,
          buffer pool size is automatically adjusted to a value that is
          equal to or a multiple of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
       <code class="literal">
        innodb_buffer_pool_chunk_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      can
          be set dynamically, which allows you to resize the buffer pool
          without restarting the server. The
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status">
       <code class="literal">
        Innodb_buffer_pool_resize_status
       </code>
      </a>
      status variable reports the status of online buffer pool
          resizing operations. See
      <a class="xref" href="innodb-buffer-pool-resize.html" title="17.8.3.1 Configuring InnoDB Buffer Pool Size">
       Section 17.8.3.1, “Configuring InnoDB Buffer Pool Size”
      </a>
      for more
          information.
     </p>
     <p>
      If the server is started with
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
       <code class="option">
        --innodb-dedicated-server
       </code>
      </a>
      , the
          value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
       <code class="literal">
        innodb_buffer_pool_size
       </code>
      </a>
      is
          set automatically if it is not explicitly defined. For more
          information, see
      <a class="xref" href="innodb-dedicated-server.html" title="17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server">
       Section 17.8.12, “Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_change_buffer_max_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffer_max_size">
       <code class="literal">
        innodb_change_buffer_max_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156585376">
     </a>
     <a class="indexterm" name="idm46045156584272">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_change_buffer_max_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-change-buffer-max-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffer_max_size">
            innodb_change_buffer_max_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           25
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Maximum size for the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_change_buffer" title="change buffer">
       change buffer
      </a>
      , as a
          percentage of the total size of the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      . You might
          increase this value for a MySQL server with heavy insert,
          update, and delete activity, or decrease it for a MySQL server
          with unchanging data used for reporting. For more information,
          see
      <a class="xref" href="innodb-change-buffer.html" title="17.5.2 Change Buffer">
       Section 17.5.2, “Change Buffer”
      </a>
      . For general I/O
          tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_change_buffering">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering">
       <code class="literal">
        innodb_change_buffering
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156550784">
     </a>
     <a class="indexterm" name="idm46045156549744">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_change_buffering">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-change-buffering=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering">
            innodb_change_buffering
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           none
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            none
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            inserts
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            deletes
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            changes
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            purges
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            all
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Whether
      <code class="literal">
       InnoDB
      </code>
      performs
      <a class="link" href="glossary.html#glos_change_buffering" title="change buffering">
       change buffering
      </a>
      ,
          an optimization that delays write operations to secondary
          indexes so that the I/O operations can be performed
          sequentially. Permitted values are described in the following
          table. Values may also be specified numerically.
     </p>
     <div class="table">
      <a name="innodb-change-buffer-permitted-values">
      </a>
      <p class="title">
       <b>
        Table 17.24 Permitted Values for innodb_change_buffering
       </b>
      </p>
      <div class="table-contents">
       <table summary="Permitted values for the innodb_chansge_buffering variable. The first column defines the value. The second column describes the option effect.">
        <colgroup>
         <col style="width: 20%"/>
         <col style="width: 20%"/>
         <col style="width: 60%"/>
        </colgroup>
        <thead>
         <tr>
          <th scope="col">
           Value
          </th>
          <th scope="col">
           Numeric Value
          </th>
          <th scope="col">
           Description
          </th>
         </tr>
        </thead>
        <tbody>
         <tr>
          <th scope="row">
           <code class="literal">
            none
           </code>
          </th>
          <td>
           <code class="literal">
            0
           </code>
          </td>
          <td>
           Default. Do not buffer any operations.
          </td>
         </tr>
         <tr>
          <th scope="row">
           <code class="literal">
            inserts
           </code>
          </th>
          <td>
           <code class="literal">
            1
           </code>
          </td>
          <td>
           Buffer insert operations.
          </td>
         </tr>
         <tr>
          <th scope="row">
           <code class="literal">
            deletes
           </code>
          </th>
          <td>
           <code class="literal">
            2
           </code>
          </td>
          <td>
           Buffer delete marking operations; strictly speaking, the writes that
                mark index records for later deletion during a purge
                operation.
          </td>
         </tr>
         <tr>
          <th scope="row">
           <code class="literal">
            changes
           </code>
          </th>
          <td>
           <code class="literal">
            3
           </code>
          </td>
          <td>
           Buffer inserts and delete-marking operations.
          </td>
         </tr>
         <tr>
          <th scope="row">
           <code class="literal">
            purges
           </code>
          </th>
          <td>
           <code class="literal">
            4
           </code>
          </td>
          <td>
           Buffer the physical deletion operations that happen in the background.
          </td>
         </tr>
         <tr>
          <th scope="row">
           <code class="literal">
            all
           </code>
          </th>
          <td>
           <code class="literal">
            5
           </code>
          </td>
          <td>
           Buffer inserts, delete-marking operations, and purges.
          </td>
         </tr>
        </tbody>
       </table>
      </div>
     </div>
     <br class="table-break"/>
     <p>
      Before MySQL 8.4, the default value was
      <code class="literal">
       all
      </code>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-change-buffer.html" title="17.5.2 Change Buffer">
       Section 17.5.2, “Change Buffer”
      </a>
      . For general I/O tuning
          advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_change_buffering_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering_debug">
       <code class="literal">
        innodb_change_buffering_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156479408">
     </a>
     <a class="indexterm" name="idm46045156478320">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_change_buffering_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-change-buffering-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_change_buffering_debug">
            innodb_change_buffering_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Sets a debug flag for
      <code class="literal">
       InnoDB
      </code>
      change
          buffering. A value of 1 forces all changes to the change
          buffer. A value of 2 causes an unexpected exit at merge. A
          default value of 0 indicates that the change buffering debug
          flag is not set. This option is only available when debugging
          support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_checkpoint_disabled">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_checkpoint_disabled">
       <code class="literal">
        innodb_checkpoint_disabled
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156446208">
     </a>
     <a class="indexterm" name="idm46045156445104">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_checkpoint_disabled">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-checkpoint-disabled[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_checkpoint_disabled">
            innodb_checkpoint_disabled
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This is a debug option that is only intended for expert
          debugging use. It disables checkpoints so that a deliberate
          server exit always initiates
      <code class="literal">
       InnoDB
      </code>
      recovery. It should only be enabled for a short interval,
          typically before running DML operations that write redo log
          entries that would require recovery following a server exit.
          This option is only available if debugging support is compiled
          in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_checksum_algorithm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_checksum_algorithm">
       <code class="literal">
        innodb_checksum_algorithm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156417712">
     </a>
     <a class="indexterm" name="idm46045156416608">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_checksum_algorithm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-checksum-algorithm=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_checksum_algorithm">
            innodb_checksum_algorithm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           crc32
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            crc32
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            strict_crc32
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            innodb
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            strict_innodb
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            none
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            strict_none
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies how to generate and verify the
      <a class="link" href="glossary.html#glos_checksum" title="checksum">
       checksum
      </a>
      stored in the
          disk blocks of
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_tablespace" title="tablespace">
       tablespaces
      </a>
      . The
          default value for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_checksum_algorithm">
       <code class="literal">
        innodb_checksum_algorithm
       </code>
      </a>
      is
      <code class="literal">
       crc32
      </code>
      .
     </p>
     <p>
      The value
      <code class="literal">
       innodb
      </code>
      is backward-compatible
          with earlier versions of MySQL. The value
      <code class="literal">
       crc32
      </code>
      uses an algorithm that is faster to
          compute the checksum for every modified block, and to check
          the checksums for each disk read. It scans blocks 64 bits at a
          time, which is faster than the
      <code class="literal">
       innodb
      </code>
      checksum algorithm, which scans blocks 8 bits at a time. The
          value
      <code class="literal">
       none
      </code>
      writes a constant value in the
          checksum field rather than computing a value based on the
          block data. The blocks in a tablespace can use a mix of old,
          new, and no checksum values, being updated gradually as the
          data is modified; once blocks in a tablespace are modified to
          use the
      <code class="literal">
       crc32
      </code>
      algorithm, the associated
          tables cannot be read by earlier versions of MySQL.
     </p>
     <p>
      The strict form of a checksum algorithm reports an error if it
          encounters a valid but non-matching checksum value in a
          tablespace. It is recommended that you only use strict
          settings in a new instance, to set up tablespaces for the
          first time. Strict settings are somewhat faster, because they
          do not need to compute all checksum values during disk reads.
     </p>
     <p>
      The following table shows the difference between the
      <code class="literal">
       none
      </code>
      ,
      <code class="literal">
       innodb
      </code>
      , and
      <code class="literal">
       crc32
      </code>
      option values, and their strict
          counterparts.
      <code class="literal">
       none
      </code>
      ,
      <code class="literal">
       innodb
      </code>
      , and
      <code class="literal">
       crc32
      </code>
      write
          the specified type of checksum value into each data block, but
          for compatibility accept other checksum values when verifying
          a block during a read operation. Strict settings also accept
          valid checksum values but print an error message when a valid
          non-matching checksum value is encountered. Using the strict
          form can make verification faster if all
      <code class="literal">
       InnoDB
      </code>
      data files in an instance are
          created under an identical
      <a class="link" href="innodb-parameters.html#sysvar_innodb_checksum_algorithm">
       <code class="literal">
        innodb_checksum_algorithm
       </code>
      </a>
      value.
     </p>
     <div class="table">
      <a name="innodb-checksum-algorithm-values">
      </a>
      <p class="title">
       <b>
        Table 17.25 Permitted innodb_checksum_algorithm Values
       </b>
      </p>
      <div class="table-contents">
       <table summary="Permitted values for the innodb_checksum_algorithm variable. The first column defines the checksum value. The second column describes the generated checksum. The third column describes compatible checksums.">
        <colgroup>
         <col style="width: 20%"/>
         <col style="width: 40%"/>
         <col style="width: 40%"/>
        </colgroup>
        <thead>
         <tr>
          <th scope="col">
           Value
          </th>
          <th scope="col">
           Generated checksum (when writing)
          </th>
          <th scope="col">
           Permitted checksums (when reading)
          </th>
         </tr>
        </thead>
        <tbody>
         <tr>
          <th scope="row">
           none
          </th>
          <td>
           A constant number.
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
          </td>
         </tr>
         <tr>
          <th scope="row">
           innodb
          </th>
          <td>
           A checksum calculated in software, using the original algorithm from
           <code class="literal">
            InnoDB
           </code>
           .
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
          </td>
         </tr>
         <tr>
          <th scope="row">
           crc32
          </th>
          <td>
           A checksum calculated using the
           <code class="literal">
            crc32
           </code>
           algorithm,
                possibly done with a hardware assist.
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
          </td>
         </tr>
         <tr>
          <th scope="row">
           strict_none
          </th>
          <td>
           A constant number
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
           <code class="literal">
            InnoDB
           </code>
           prints an error message if a
                valid but non-matching checksum is encountered.
          </td>
         </tr>
         <tr>
          <th scope="row">
           strict_innodb
          </th>
          <td>
           A checksum calculated in software, using the original algorithm from
           <code class="literal">
            InnoDB
           </code>
           .
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
           <code class="literal">
            InnoDB
           </code>
           prints an error message if a
                valid but non-matching checksum is encountered.
          </td>
         </tr>
         <tr>
          <th scope="row">
           strict_crc32
          </th>
          <td>
           A checksum calculated using the
           <code class="literal">
            crc32
           </code>
           algorithm,
                possibly done with a hardware assist.
          </td>
          <td>
           Any of the checksums generated by
           <code class="literal">
            none
           </code>
           ,
           <code class="literal">
            innodb
           </code>
           , or
           <code class="literal">
            crc32
           </code>
           .
           <code class="literal">
            InnoDB
           </code>
           prints an error message if a
                valid but non-matching checksum is encountered.
          </td>
         </tr>
        </tbody>
       </table>
      </div>
     </div>
     <br class="table-break"/>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_cmp_per_index_enabled">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_cmp_per_index_enabled">
       <code class="literal">
        innodb_cmp_per_index_enabled
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156319904">
     </a>
     <a class="indexterm" name="idm46045156318800">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_cmp_per_index_enabled">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-cmp-per-index-enabled[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_cmp_per_index_enabled">
            innodb_cmp_per_index_enabled
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables per-index compression-related statistics in the
          Information Schema
      <a class="link" href="information-schema-innodb-cmp-per-index-table.html" title="28.4.8 The INFORMATION_SCHEMA INNODB_CMP_PER_INDEX and INNODB_CMP_PER_INDEX_RESET Tables">
       <code class="literal">
        INNODB_CMP_PER_INDEX
       </code>
      </a>
      table.
          Because these statistics can be expensive to gather, only
          enable this option on development, test, or replica instances
          during performance tuning related to
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_compression" title="compression">
       compressed
      </a>
      tables.
     </p>
     <p>
      For more information, see
      <a class="xref" href="information-schema-innodb-cmp-per-index-table.html" title="28.4.8 The INFORMATION_SCHEMA INNODB_CMP_PER_INDEX and INNODB_CMP_PER_INDEX_RESET Tables">
       Section 28.4.8, “The INFORMATION_SCHEMA INNODB_CMP_PER_INDEX and
      INNODB_CMP_PER_INDEX_RESET Tables”
      </a>
      ,
          and
      <a class="xref" href="innodb-compression-tuning-monitoring.html" title="17.9.1.4 Monitoring InnoDB Table Compression at Runtime">
       Section 17.9.1.4, “Monitoring InnoDB Table Compression at Runtime”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_commit_concurrency">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_commit_concurrency">
       <code class="literal">
        innodb_commit_concurrency
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156289232">
     </a>
     <a class="indexterm" name="idm46045156288128">
     </a>
     <a class="indexterm" name="idm46045156286624">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_commit_concurrency">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-commit-concurrency=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_commit_concurrency">
            innodb_commit_concurrency
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of
      <a class="link" href="glossary.html#glos_thread" title="thread">
       threads
      </a>
      that
          can
      <a class="link" href="glossary.html#glos_commit" title="commit">
       commit
      </a>
      at the same
          time. A value of 0 (the default) permits any number of
      <a class="link" href="glossary.html#glos_transaction" title="transaction">
       transactions
      </a>
      to commit
          simultaneously.
     </p>
     <p>
      The value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_commit_concurrency">
       <code class="literal">
        innodb_commit_concurrency
       </code>
      </a>
      cannot be changed at runtime from zero to nonzero or vice
          versa. The value can be changed from one nonzero value to
          another.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_compress_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compress_debug">
       <code class="literal">
        innodb_compress_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156252688">
     </a>
     <a class="indexterm" name="idm46045156251616">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_compress_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-compress-debug=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_compress_debug">
            innodb_compress_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           none
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            none
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            zlib
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            lz4
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            lz4hc
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Compresses all tables using a specified compression algorithm
          without having to define a
      <code class="literal">
       COMPRESSION
      </code>
      attribute for each table. This option is only available if
          debugging support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-page-compression.html" title="17.9.2 InnoDB Page Compression">
       Section 17.9.2, “InnoDB Page Compression”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_compression_failure_threshold_pct">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_failure_threshold_pct">
       <code class="literal">
        innodb_compression_failure_threshold_pct
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156217632">
     </a>
     <a class="indexterm" name="idm46045156216512">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_compression_failure_threshold_pct">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-compression-failure-threshold-pct=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_failure_threshold_pct">
            innodb_compression_failure_threshold_pct
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           5
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the compression failure rate threshold for a table, as
          a percentage, at which point MySQL begins adding padding
          within
      <a class="link" href="glossary.html#glos_compression" title="compression">
       compressed
      </a>
      pages to avoid expensive
      <a class="link" href="glossary.html#glos_compression_failure" title="compression failure">
       compression
          failures
      </a>
      . When this threshold is passed, MySQL begins
          to leave additional free space within each new compressed
          page, dynamically adjusting the amount of free space up to the
          percentage of page size specified by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_pad_pct_max">
       <code class="literal">
        innodb_compression_pad_pct_max
       </code>
      </a>
      .
          A value of zero disables the mechanism that monitors
          compression efficiency and dynamically adjusts the padding
          amount.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-compression-oltp.html" title="17.9.1.6 Compression for OLTP Workloads">
       Section 17.9.1.6, “Compression for OLTP Workloads”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_compression_level">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_level">
       <code class="literal">
        innodb_compression_level
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156182336">
     </a>
     <a class="indexterm" name="idm46045156181232">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_compression_level">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-compression-level=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_level">
            innodb_compression_level
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           6
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           9
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the level of zlib compression to use for
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_compression" title="compression">
       compressed
      </a>
      tables and
          indexes. A higher value lets you fit more data onto a storage
          device, at the expense of more CPU overhead during
          compression. A lower value lets you reduce CPU overhead when
          storage space is not critical, or you expect the data is not
          especially compressible.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-compression-oltp.html" title="17.9.1.6 Compression for OLTP Workloads">
       Section 17.9.1.6, “Compression for OLTP Workloads”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_compression_pad_pct_max">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_pad_pct_max">
       <code class="literal">
        innodb_compression_pad_pct_max
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156148784">
     </a>
     <a class="indexterm" name="idm46045156147680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_compression_pad_pct_max">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-compression-pad-pct-max=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_pad_pct_max">
            innodb_compression_pad_pct_max
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           75
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the maximum percentage that can be reserved as free
          space within each compressed
      <a class="link" href="glossary.html#glos_page" title="page">
       page
      </a>
      , allowing room to
          reorganize the data and modification log within the page when
          a
      <a class="link" href="glossary.html#glos_compression" title="compression">
       compressed
      </a>
      table or
          index is updated and the data might be recompressed. Only
          applies when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_compression_failure_threshold_pct">
       <code class="literal">
        innodb_compression_failure_threshold_pct
       </code>
      </a>
      is set to a nonzero value, and the rate of
      <a class="link" href="glossary.html#glos_compression_failure" title="compression failure">
       compression
          failures
      </a>
      passes the cutoff point.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-compression-oltp.html" title="17.9.1.6 Compression for OLTP Workloads">
       Section 17.9.1.6, “Compression for OLTP Workloads”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_concurrency_tickets">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156112896">
     </a>
     <a class="indexterm" name="idm46045156111792">
     </a>
     <a class="indexterm" name="idm46045156110288">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_concurrency_tickets">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-concurrency-tickets=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
            innodb_concurrency_tickets
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           5000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Determines the number of
      <a class="link" href="glossary.html#glos_thread" title="thread">
       threads
      </a>
      that can enter
      <code class="literal">
       InnoDB
      </code>
      concurrently. A thread is placed in
          a queue when it tries to enter
      <code class="literal">
       InnoDB
      </code>
      if
          the number of threads has already reached the concurrency
          limit. When a thread is permitted to enter
      <code class="literal">
       InnoDB
      </code>
      , it is given a number of
      <span class="quote">
       “
       <span class="quote">
        tickets
       </span>
       ”
      </span>
      equal to the value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      ,
          and the thread can enter and leave
      <code class="literal">
       InnoDB
      </code>
      freely until it has used up its tickets. After that point, the
          thread again becomes subject to the concurrency check (and
          possible queuing) the next time it tries to enter
      <code class="literal">
       InnoDB
      </code>
      . The default value is 5000.
     </p>
     <p>
      With a small
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      value, small transactions that only need to process a few rows
          compete fairly with larger transactions that process many
          rows. The disadvantage of a small
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      value is that large transactions must loop through the queue
          many times before they can complete, which extends the amount
          of time required to complete their task.
     </p>
     <p>
      With a large
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      value, large transactions spend less time waiting for a
          position at the end of the queue (controlled by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      )
          and more time retrieving rows. Large transactions also require
          fewer trips through the queue to complete their task. The
          disadvantage of a large
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      value is that too many large transactions running at the same
          time can starve smaller transactions by making them wait a
          longer time before executing.
     </p>
     <p>
      With a nonzero
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      value, you may need to adjust the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_concurrency_tickets">
       <code class="literal">
        innodb_concurrency_tickets
       </code>
      </a>
      value up or down to find the optimal balance between larger
          and smaller transactions. The
      <code class="literal">
       SHOW ENGINE INNODB
          STATUS
      </code>
      report shows the number of tickets remaining
          for an executing transaction in its current pass through the
          queue. This data may also be obtained from the
      <code class="literal">
       TRX_CONCURRENCY_TICKETS
      </code>
      column of the
          Information Schema
      <a class="link" href="information-schema-innodb-trx-table.html" title="28.4.28 The INFORMATION_SCHEMA INNODB_TRX Table">
       <code class="literal">
        INNODB_TRX
       </code>
      </a>
      table.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-thread_concurrency.html" title="17.8.4 Configuring Thread Concurrency for InnoDB">
       Section 17.8.4, “Configuring Thread Concurrency for InnoDB”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_data_file_path">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
       <code class="literal">
        innodb_data_file_path
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156058832">
     </a>
     <a class="indexterm" name="idm46045156057792">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_data_file_path">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-data-file-path=file_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
            innodb_data_file_path
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ibdata1:12M:autoextend
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the name, size, and attributes of
      <code class="literal">
       InnoDB
      </code>
      system tablespace data files. If you
          do not specify a value for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
       <code class="literal">
        innodb_data_file_path
       </code>
      </a>
      , the
          default behavior is to create a single auto-extending data
          file, slightly larger than 12MB, named
      <code class="filename">
       ibdata1
      </code>
      .
     </p>
     <p>
      The full syntax for a data file specification includes the
          file name, file size,
      <code class="literal">
       autoextend
      </code>
      attribute,
          and
      <code class="literal">
       max
      </code>
      attribute:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa64702669"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none"><em class="replaceable">file_name</em>:<em class="replaceable">file_size</em>[:autoextend[:max:<em class="replaceable">max_file_size</em>]]</code></pre>
     </div>
     <p>
      File sizes are specified in kilobytes, megabytes, or gigabytes
          by appending
      <code class="literal">
       K
      </code>
      ,
      <code class="literal">
       M
      </code>
      or
      <code class="literal">
       G
      </code>
      to the size value. If specifying the data
          file size in kilobytes, do so in multiples of 1024. Otherwise,
          KB values are rounded to nearest megabyte (MB) boundary. The
          sum of file sizes must be, at a minimum, slightly larger than
          12MB.
     </p>
     <p>
      For additional configuration information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-data-file-configuration" title="System Tablespace Data File Configuration">
       System Tablespace Data File Configuration
      </a>
      . For
          resizing instructions, see
      <a class="xref" href="innodb-system-tablespace.html#innodb-resize-system-tablespace" title="Resizing the System Tablespace">
       Resizing the System Tablespace
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_data_home_dir">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045156021632">
     </a>
     <a class="indexterm" name="idm46045156020592">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_data_home_dir">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-data-home-dir=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
            innodb_data_home_dir
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The common part of the directory path for
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_system_tablespace" title="system tablespace">
       system
          tablespace
      </a>
      data files. The default value is the MySQL
      <code class="filename">
       data
      </code>
      directory. The setting is
          concatenated with the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
       <code class="literal">
        innodb_data_file_path
       </code>
      </a>
      setting, unless that setting is defined with an absolute path.
     </p>
     <p>
      A trailing slash is required when specifying a value for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
      . For
          example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa58117203"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">innodb_data_home_dir</span> <span class="token attr-value"><span class="token punctuation">=</span> /path/to/myibdata/</span></code></pre>
     </div>
     <p>
      This setting does not affect the location of
      <a class="link" href="glossary.html#glos_file_per_table" title="file-per-table">
       file-per-table
      </a>
      tablespaces.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-init-startup-configuration.html" title="17.8.1 InnoDB Startup Configuration">
       Section 17.8.1, “InnoDB Startup Configuration”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ddl_buffer_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_buffer_size">
       <code class="literal">
        innodb_ddl_buffer_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155989552">
     </a>
     <a class="indexterm" name="idm46045155988512">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ddl_buffer_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ddl-buffer-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_buffer_size">
            innodb_ddl_buffer_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1048576
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           65536
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum buffer size for DDL operations. The
          default setting is 1048576 bytes (approximately 1 MB). Applies
          to online DDL operations that create or rebuild secondary
          indexes. See
      <a class="xref" href="online-ddl-memory-management.html" title="17.12.4 Online DDL Memory Management">
       Section 17.12.4, “Online DDL Memory Management”
      </a>
      .
          The maximum buffer size per DDL thread is the maximum buffer
          size divided by the number of DDL threads
          (
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_buffer_size">
       <code class="literal">
        innodb_ddl_buffer_size
       </code>
      </a>
      /
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_threads">
       <code class="literal">
        innodb_ddl_threads
       </code>
      </a>
      ).
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ddl_log_crash_reset_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_log_crash_reset_debug">
       <code class="literal">
        innodb_ddl_log_crash_reset_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155953408">
     </a>
     <a class="indexterm" name="idm46045155952304">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ddl_log_crash_reset_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ddl-log-crash-reset-debug[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_log_crash_reset_debug">
            innodb_ddl_log_crash_reset_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enable this debug option to reset DDL log crash injection
          counters to 1. This option is only available when debugging
          support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ddl_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_threads">
       <code class="literal">
        innodb_ddl_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155925920">
     </a>
     <a class="indexterm" name="idm46045155924880">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ddl_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ddl-threads=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ddl_threads">
            innodb_ddl_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           4
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum number of parallel threads for the sort
          and build phases of index creation. Applies to online DDL
          operations that create or rebuild secondary indexes. For
          related information, see
      <a class="xref" href="online-ddl-parallel-thread-configuration.html" title="17.12.5 Configuring Parallel Threads for Online DDL Operations">
       Section 17.12.5, “Configuring Parallel Threads for Online DDL Operations”
      </a>
      ,
          and
      <a class="xref" href="online-ddl-memory-management.html" title="17.12.4 Online DDL Memory Management">
       Section 17.12.4, “Online DDL Memory Management”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_deadlock_detect">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_deadlock_detect">
       <code class="literal">
        innodb_deadlock_detect
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155893696">
     </a>
     <a class="indexterm" name="idm46045155892656">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_deadlock_detect">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-deadlock-detect[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_deadlock_detect">
            innodb_deadlock_detect
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This option is used to disable deadlock detection. On high
          concurrency systems, deadlock detection can cause a slowdown
          when numerous threads wait for the same lock. At times, it may
          be more efficient to disable deadlock detection and rely on
          the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
      setting for transaction rollback when a deadlock occurs.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-deadlock-detection.html" title="17.7.5.2 Deadlock Detection">
       Section 17.7.5.2, “Deadlock Detection”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_default_row_format">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
       <code class="literal">
        innodb_default_row_format
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155865408">
     </a>
     <a class="indexterm" name="idm46045155864304">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_default_row_format">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-default-row-format=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
            innodb_default_row_format
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           DYNAMIC
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            REDUNDANT
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            COMPACT
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            DYNAMIC
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
       <code class="literal">
        innodb_default_row_format
       </code>
      </a>
      option defines the default row format for
      <code class="literal">
       InnoDB
      </code>
      tables and user-created temporary
          tables. The default setting is
      <code class="literal">
       DYNAMIC
      </code>
      .
          Other permitted values are
      <code class="literal">
       COMPACT
      </code>
      and
      <code class="literal">
       REDUNDANT
      </code>
      . The
      <code class="literal">
       COMPRESSED
      </code>
      row format, which is not
          supported for use in the
      <a class="link" href="glossary.html#glos_system_tablespace" title="system tablespace">
       system
          tablespace
      </a>
      , cannot be defined as the default.
     </p>
     <p>
      Newly created tables use the row format defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
       <code class="literal">
        innodb_default_row_format
       </code>
      </a>
      when a
      <code class="literal">
       ROW_FORMAT
      </code>
      option is not specified
          explicitly or when
      <code class="literal">
       ROW_FORMAT=DEFAULT
      </code>
      is
          used.
     </p>
     <p>
      When a
      <code class="literal">
       ROW_FORMAT
      </code>
      option is not specified
          explicitly or when
      <code class="literal">
       ROW_FORMAT=DEFAULT
      </code>
      is
          used, any operation that rebuilds a table also silently
          changes the row format of the table to the format defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
       <code class="literal">
        innodb_default_row_format
       </code>
      </a>
      .
          For more information, see
      <a class="xref" href="innodb-row-format.html#innodb-row-format-defining" title="Defining the Row Format of a Table">
       Defining the Row Format of a Table
      </a>
      .
     </p>
     <p>
      Internal
      <code class="literal">
       InnoDB
      </code>
      temporary tables created by
          the server to process queries use the
      <code class="literal">
       DYNAMIC
      </code>
      row format, regardless of the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_default_row_format">
       <code class="literal">
        innodb_default_row_format
       </code>
      </a>
      setting.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_directories">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155818432">
     </a>
     <a class="indexterm" name="idm46045155817392">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_directories">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-directories=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
            innodb_directories
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines directories to scan at startup for tablespace files.
          This option is used when moving or restoring tablespace files
          to a new location while the server is offline. It is also used
          to specify directories of tablespace files created using an
          absolute path or that reside outside of the data directory.
     </p>
     <p>
      Tablespace discovery during crash recovery relies on the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
      setting to
          identify tablespaces referenced in the redo logs. For more
          information, see
      <a class="xref" href="innodb-recovery.html#innodb-recovery-tablespace-discovery" title="Tablespace Discovery During Crash Recovery">
       Tablespace Discovery During Crash Recovery
      </a>
      .
     </p>
     <p>
      The default value is NULL, but directories defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
      ,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
       <code class="literal">
        innodb_undo_directory
       </code>
      </a>
      , and
      <a class="link" href="server-system-variables.html#sysvar_datadir">
       <code class="literal">
        datadir
       </code>
      </a>
      are always appended
          to the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
      argument value when
      <code class="literal">
       InnoDB
      </code>
      builds a list of
          directories to scan at startup. These directories are appended
          regardless of whether an
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
      setting is
          specified explicitly.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
      may be
          specified as an option in a startup command or in a MySQL
          option file. Quotes surround the argument value because
          otherwise some command interpreters interpret semicolon
          (
      <code class="literal">
       ;
      </code>
      ) as a special character. (For example,
          Unix shells treat it as a command terminator.)
     </p>
     <p>
      Startup command:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa21029187"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysqld <span class="token constant">--innodb-directories</span>=<span class="token atrule">"<em class="replaceable">directory_path_1</em>;<em class="replaceable">directory_path_2</em>"</span></code></pre>
     </div>
     <p>
      MySQL option file:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa50695958"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">innodb_directories</span><span class="token attr-value"><span class="token punctuation">=</span>"<em class="replaceable">directory_path_1</em>;<em class="replaceable">directory_path_2</em>"</span></code></pre>
     </div>
     <p>
      Wildcard expressions cannot be used to specify directories.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_directories">
       <code class="literal">
        innodb_directories
       </code>
      </a>
      scan
          also traverses the subdirectories of specified directories.
          Duplicate directories and subdirectories are discarded from
          the list of directories to be scanned.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-moving-data-files-offline.html" title="17.6.3.6 Moving Tablespace Files While the Server is Offline">
       Section 17.6.3.6, “Moving Tablespace Files While the Server is Offline”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_disable_sort_file_cache">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_disable_sort_file_cache">
       <code class="literal">
        innodb_disable_sort_file_cache
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155771600">
     </a>
     <a class="indexterm" name="idm46045155770496">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_disable_sort_file_cache">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-disable-sort-file-cache[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_disable_sort_file_cache">
            innodb_disable_sort_file_cache
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Disables the operating system file system cache for merge-sort
          temporary files. The effect is to open such files with the
          equivalent of
      <code class="literal">
       O_DIRECT
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_doublewrite">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
       <code class="literal">
        innodb_doublewrite
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155745008">
     </a>
     <a class="indexterm" name="idm46045155743968">
     </a>
     <a class="indexterm" name="idm46045155742480">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_doublewrite">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-doublewrite=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
            innodb_doublewrite
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            ON
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            OFF
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            DETECT_AND_RECOVER
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            DETECT_ONLY
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
       <code class="literal">
        innodb_doublewrite
       </code>
      </a>
      variable controls doublewrite buffering. Doublewrite buffering
          is enabled by default in most cases.
     </p>
     <p>
      You can set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
       <code class="literal">
        innodb_doublewrite
       </code>
      </a>
      to
      <code class="literal">
       ON
      </code>
      or
      <code class="literal">
       OFF
      </code>
      when starting
          the server to enable or disable doublewrite buffering,
          respectively.
      <code class="literal">
       DETECT_AND_RECOVER
      </code>
      is the
          same as
      <code class="literal">
       ON
      </code>
      . With this setting, except that
          the doublewrite buffer is fully enabled, with database page
          content written to the doublewrite buffer where it is accessed
          during recovery to fix incomplete page writes. With
      <code class="literal">
       DETECT_ONLY
      </code>
      , only metadata is written to
          the doublewrite buffer. Database page content is not written
          to the doublewrite buffer, and recovery does not use the
          doublewrite buffer to fix incomplete page writes. This
          lightweight setting is intended for detecting incomplete page
          writes only.
     </p>
     <p>
      MySQL supports dynamic changes to the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
       <code class="literal">
        innodb_doublewrite
       </code>
      </a>
      setting
          that enables the doublewrite buffer, between
      <code class="literal">
       ON
      </code>
      ,
      <code class="literal">
       DETECT_AND_RECOVER
      </code>
      ,
          and
      <code class="literal">
       DETECT_ONLY
      </code>
      . MySQL does not support
          dynamic changes between a setting that enables the doublewrite
          buffer and
      <code class="literal">
       OFF
      </code>
      or vice versa.
     </p>
     <p>
      If the doublewrite buffer is located on a Fusion-io device
          that supports atomic writes, the doublewrite buffer is
          automatically disabled and data file writes are performed
          using Fusion-io atomic writes instead. However, be aware that
          the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite">
       <code class="literal">
        innodb_doublewrite
       </code>
      </a>
      setting is global. When the doublewrite buffer is disabled, it
          is disabled for all data files including those that do not
          reside on Fusion-io hardware. This feature is only supported
          on Fusion-io hardware and is only enabled for Fusion-io NVMFS
          on Linux. To take full advantage of this feature, an
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
      setting
          of
      <code class="literal">
       O_DIRECT
      </code>
      is recommended.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-doublewrite-buffer.html" title="17.6.4 Doublewrite Buffer">
       Section 17.6.4, “Doublewrite Buffer”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_doublewrite_batch_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_batch_size">
       <code class="literal">
        innodb_doublewrite_batch_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155695328">
     </a>
     <a class="indexterm" name="idm46045155694240">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_doublewrite_batch_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-doublewrite-batch-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_batch_size">
            innodb_doublewrite_batch_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           256
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable was intended to represent the number of
          doublewrite pages to write in a batch. This functionality was
          replaced by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_pages">
       <code class="literal">
        innodb_doublewrite_pages
       </code>
      </a>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-doublewrite-buffer.html" title="17.6.4 Doublewrite Buffer">
       Section 17.6.4, “Doublewrite Buffer”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_doublewrite_dir">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_dir">
       <code class="literal">
        innodb_doublewrite_dir
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155662208">
     </a>
     <a class="indexterm" name="idm46045155661136">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_doublewrite_dir">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-doublewrite-dir=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_dir">
            innodb_doublewrite_dir
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the directory for doublewrite files. If no directory
          is specified, doublewrite files are created in the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
      directory, which defaults to the data directory if
          unspecified.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-doublewrite-buffer.html" title="17.6.4 Doublewrite Buffer">
       Section 17.6.4, “Doublewrite Buffer”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_doublewrite_files">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_files">
       <code class="literal">
        innodb_doublewrite_files
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155636448">
     </a>
     <a class="indexterm" name="idm46045155635360">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_doublewrite_files">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-doublewrite-files=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_files">
            innodb_doublewrite_files
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           256
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the number of doublewrite files. By default, two
          doublewrite files are created for each buffer pool instance.
     </p>
     <p>
      At a minimum, there are two doublewrite files. The maximum
          number of doublewrite files is two times the number of buffer
          pool instances. (The number of buffer pool instances is
          controlled by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      variable.)
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-doublewrite-buffer.html" title="17.6.4 Doublewrite Buffer">
       Section 17.6.4, “Doublewrite Buffer”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_doublewrite_pages">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_pages">
       <code class="literal">
        innodb_doublewrite_pages
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155602752">
     </a>
     <a class="indexterm" name="idm46045155601664">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_doublewrite_pages">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-doublewrite-pages=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_pages">
            innodb_doublewrite_pages
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           128
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           512
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum number of doublewrite pages per thread for
          a batch write. If no value is specified,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_doublewrite_pages">
       <code class="literal">
        innodb_doublewrite_pages
       </code>
      </a>
      defaults to 128.
     </p>
     <p>
      Before MySQL 8.4, the default value was the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
       <code class="literal">
        innodb_write_io_threads
       </code>
      </a>
      value, which is 4 by default.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-doublewrite-buffer.html" title="17.6.4 Doublewrite Buffer">
       Section 17.6.4, “Doublewrite Buffer”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_extend_and_initialize">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_extend_and_initialize">
       <code class="literal">
        innodb_extend_and_initialize
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155567952">
     </a>
     <a class="indexterm" name="idm46045155566848">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_extend_and_initialize">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb=extend-and-initialize[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_extend_and_initialize">
            innodb_extend_and_initialize
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls how space is allocated to file-per-table and general
          tablespaces on Linux systems.
     </p>
     <p>
      When enabled,
      <code class="literal">
       InnoDB
      </code>
      writes NULLs to newly
          allocated pages. When disabled, space is allocated using
      <code class="literal">
       posix_fallocate()
      </code>
      calls, which reserve
          space without physically writing NULLs.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-optimize-tablespace-page-allocation.html" title="17.6.3.8 Optimizing Tablespace Space Allocation on Linux">
       Section 17.6.3.8, “Optimizing Tablespace Space Allocation on Linux”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_fast_shutdown">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fast_shutdown">
       <code class="literal">
        innodb_fast_shutdown
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155538784">
     </a>
     <a class="indexterm" name="idm46045155537744">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_fast_shutdown">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-fast-shutdown=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_fast_shutdown">
            innodb_fast_shutdown
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            0
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            1
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            2
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_shutdown" title="shutdown">
       shutdown
      </a>
      mode. If the
          value is 0,
      <code class="literal">
       InnoDB
      </code>
      does a
      <a class="link" href="glossary.html#glos_slow_shutdown" title="slow shutdown">
       slow shutdown
      </a>
      , a
          full
      <a class="link" href="glossary.html#glos_purge" title="purge">
       purge
      </a>
      and a change
          buffer merge before shutting down. If the value is 1 (the
          default),
      <code class="literal">
       InnoDB
      </code>
      skips these operations at
          shutdown, a process known as a
      <a class="link" href="glossary.html#glos_fast_shutdown" title="fast shutdown">
       fast shutdown
      </a>
      . If
          the value is 2,
      <code class="literal">
       InnoDB
      </code>
      flushes its logs and
          shuts down cold, as if MySQL had crashed; no committed
          transactions are lost, but the
      <a class="link" href="glossary.html#glos_crash_recovery" title="crash recovery">
       crash recovery
      </a>
      operation makes the next startup take longer.
     </p>
     <p>
      The slow shutdown can take minutes, or even hours in extreme
          cases where substantial amounts of data are still buffered.
          Use the slow shutdown technique before upgrading or
          downgrading between MySQL major releases, so that all data
          files are fully prepared in case the upgrade process updates
          the file format.
     </p>
     <p>
      Use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fast_shutdown">
       <code class="literal">
        innodb_fast_shutdown=2
       </code>
      </a>
      in
          emergency or troubleshooting situations, to get the absolute
          fastest shutdown if data is at risk of corruption.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_fil_make_page_dirty_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
       <code class="literal">
        innodb_fil_make_page_dirty_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155498544">
     </a>
     <a class="indexterm" name="idm46045155497456">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_fil_make_page_dirty_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-fil-make-page-dirty-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
            innodb_fil_make_page_dirty_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      By default, setting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
       <code class="literal">
        innodb_fil_make_page_dirty_debug
       </code>
      </a>
      to the ID of a tablespace immediately dirties the first page
          of the tablespace. If
      <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
       <code class="literal">
        innodb_saved_page_number_debug
       </code>
      </a>
      is set to a non-default value, setting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
       <code class="literal">
        innodb_fil_make_page_dirty_debug
       </code>
      </a>
      dirties the specified page. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
       <code class="literal">
        innodb_fil_make_page_dirty_debug
       </code>
      </a>
      option is only available if debugging support is compiled in
          using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_file_per_table">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
       <code class="literal">
        innodb_file_per_table
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155460928">
     </a>
     <a class="indexterm" name="idm46045155459888">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_file_per_table">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-file-per-table[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
            innodb_file_per_table
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
       <code class="literal">
        innodb_file_per_table
       </code>
      </a>
      is
          enabled, tables are created in file-per-table tablespaces by
          default. When disabled, tables are created in the system
          tablespace by default. For information about file-per-table
          tablespaces, see
      <a class="xref" href="innodb-file-per-table-tablespaces.html" title="17.6.3.2 File-Per-Table Tablespaces">
       Section 17.6.3.2, “File-Per-Table Tablespaces”
      </a>
      . For
          information about the
      <code class="literal">
       InnoDB
      </code>
      system
          tablespace, see
      <a class="xref" href="innodb-system-tablespace.html" title="17.6.3.1 The System Tablespace">
       Section 17.6.3.1, “The System Tablespace”
      </a>
      .
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
       <code class="literal">
        innodb_file_per_table
       </code>
      </a>
      variable can be configured at runtime using a
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
          GLOBAL
       </code>
      </a>
      statement, specified on the command line at
          startup, or specified in an option file. Configuration at
          runtime requires privileges sufficient to set global system
          variables (see
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      )
          and immediately affects the operation of all connections.
     </p>
     <p>
      When a table that resides in a file-per-table tablespace is
          truncated or dropped, the freed space is returned to the
          operating system. Truncating or dropping a table that resides
          in the system tablespace only frees space in the system
          tablespace. Freed space in the system tablespace can be used
          again for
      <code class="literal">
       InnoDB
      </code>
      data but is not returned
          to the operating system, as system tablespace data files never
          shrink.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
       <code class="literal">
        innodb_file_per-table
       </code>
      </a>
      setting does not affect the creation of temporary tables;
          temporary tables are created in session temporary tablespaces.
          See
      <a class="xref" href="innodb-temporary-tablespace.html" title="17.6.3.5 Temporary Tablespaces">
       Section 17.6.3.5, “Temporary Tablespaces”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_fill_factor">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155423488">
     </a>
     <a class="indexterm" name="idm46045155422448">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_fill_factor">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-fill-factor=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
            innodb_fill_factor
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           10
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      <code class="literal">
       InnoDB
      </code>
      performs a bulk load when creating
          or rebuilding indexes. This method of index creation is known
          as a
      <span class="quote">
       “
       <span class="quote">
        sorted index build
       </span>
       ”
      </span>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
      defines
          the percentage of space on each B-tree page that is filled
          during a sorted index build, with the remaining space reserved
          for future index growth. For example, setting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
      to 80
          reserves 20 percent of the space on each B-tree page for
          future index growth. Actual percentages may vary. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
      setting is
          interpreted as a hint rather than a hard limit.
     </p>
     <p>
      An
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
      setting
          of 100 leaves 1/16 of the space in clustered index pages free
          for future index growth.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fill_factor">
       <code class="literal">
        innodb_fill_factor
       </code>
      </a>
      applies to
          both B-tree leaf and non-leaf pages. It does not apply to
          external pages used for
      <a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
       <code class="literal">
        TEXT
       </code>
      </a>
      or
      <a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
       <code class="literal">
        BLOB
       </code>
      </a>
      entries.
     </p>
     <p>
      For more information, see
      <a class="xref" href="sorted-index-builds.html" title="17.6.2.3 Sorted Index Builds">
       Section 17.6.2.3, “Sorted Index Builds”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flush_log_at_timeout">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
       <code class="literal">
        innodb_flush_log_at_timeout
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155379456">
     </a>
     <a class="indexterm" name="idm46045155378352">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flush_log_at_timeout">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flush-log-at-timeout=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
            innodb_flush_log_at_timeout
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2700
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          seconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Write and flush the logs every
      <em class="replaceable">
       <code>
        N
       </code>
      </em>
      seconds.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
       <code class="literal">
        innodb_flush_log_at_timeout
       </code>
      </a>
      allows the timeout period between flushes to be increased in
          order to reduce flushing and avoid impacting performance of
          binary log group commit. The default setting for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
       <code class="literal">
        innodb_flush_log_at_timeout
       </code>
      </a>
      is once per second.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flush_log_at_trx_commit">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
       <code class="literal">
        innodb_flush_log_at_trx_commit
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155343632">
     </a>
     <a class="indexterm" name="idm46045155342528">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flush_log_at_trx_commit">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flush-log-at-trx-commit=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
            innodb_flush_log_at_trx_commit
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            0
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            1
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            2
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls the balance between strict
      <a class="link" href="glossary.html#glos_acid" title="ACID">
       ACID
      </a>
      compliance for
      <a class="link" href="glossary.html#glos_commit" title="commit">
       commit
      </a>
      operations and
          higher performance that is possible when commit-related I/O
          operations are rearranged and done in batches. You can achieve
          better performance by changing the default value but then you
          can lose transactions in a crash.
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         The default setting of 1 is required for full ACID
              compliance. Logs are written and flushed to disk at each
              transaction commit.
        </p>
       </li>
       <li class="listitem">
        <p>
         With a setting of 0, logs are written and flushed to disk
              once per second. Transactions for which logs have not been
              flushed can be lost in a crash.
        </p>
       </li>
       <li class="listitem">
        <p>
         With a setting of 2, logs are written after each
              transaction commit and flushed to disk once per second.
              Transactions for which logs have not been flushed can be
              lost in a crash.
        </p>
       </li>
       <li class="listitem">
        <p>
         For settings 0 and 2, once-per-second flushing is not 100%
              guaranteed. Flushing may occur more frequently due to DDL
              changes and other internal
         <code class="literal">
          InnoDB
         </code>
         activities that cause logs to be flushed independently of
              the
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
          <code class="literal">
           innodb_flush_log_at_trx_commit
          </code>
         </a>
         setting, and sometimes less frequently due to scheduling
              issues. If logs are flushed once per second, up to one
              second of transactions can be lost in a crash. If logs are
              flushed more or less frequently than once per second, the
              amount of transactions that can be lost varies
              accordingly.
        </p>
       </li>
       <li class="listitem">
        <p>
         Log flushing frequency is controlled by
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_timeout">
          <code class="literal">
           innodb_flush_log_at_timeout
          </code>
         </a>
         ,
              which allows you to set log flushing frequency to
         <em class="replaceable">
          <code>
           N
          </code>
         </em>
         seconds (where
         <em class="replaceable">
          <code>
           N
          </code>
         </em>
         is
         <code class="literal">
          1 ...
              2700
         </code>
         , with a default value of 1). However, any
              unexpected
         <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
          <span class="command">
           <strong>
            mysqld
           </strong>
          </span>
         </a>
         process exit can
              erase up to
         <em class="replaceable">
          <code>
           N
          </code>
         </em>
         seconds of
              transactions.
        </p>
       </li>
       <li class="listitem">
        <p>
         DDL changes and other internal
         <code class="literal">
          InnoDB
         </code>
         activities flush the log independently of the
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
          <code class="literal">
           innodb_flush_log_at_trx_commit
          </code>
         </a>
         setting.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          InnoDB
         </code>
         <a class="link" href="glossary.html#glos_crash_recovery" title="crash recovery">
          crash recovery
         </a>
         works regardless of the
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
          <code class="literal">
           innodb_flush_log_at_trx_commit
          </code>
         </a>
         setting. Transactions are either applied entirely or
              erased entirely.
        </p>
       </li>
      </ul>
     </div>
     <p>
      For durability and consistency in a replication setup that
          uses
      <code class="literal">
       InnoDB
      </code>
      with transactions:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         If binary logging is enabled, set
         <code class="literal">
          sync_binlog=1
         </code>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         Always set
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit">
          <code class="literal">
           innodb_flush_log_at_trx_commit=1
          </code>
         </a>
         .
        </p>
       </li>
      </ul>
     </div>
     <p>
      For information on the combination of settings on a replica
          that is most resilient to unexpected halts, see
      <a class="xref" href="replication-solutions-unexpected-replica-halt.html" title="19.4.2 Handling an Unexpected Halt of a Replica">
       Section 19.4.2, “Handling an Unexpected Halt of a Replica”
      </a>
      .
     </p>
     <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Caution
      </div>
      <p>
       Many operating systems and some disk hardware fool the
            flush-to-disk operation. They may tell
       <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
        <span class="command">
         <strong>
          mysqld
         </strong>
        </span>
       </a>
       that the flush has taken place,
            even though it has not. In this case, the durability of
            transactions is not guaranteed even with the recommended
            settings, and in the worst case, a power outage can corrupt
       <code class="literal">
        InnoDB
       </code>
       data. Using a battery-backed disk
            cache in the SCSI disk controller or in the disk itself
            speeds up file flushes, and makes the operation safer. You
            can also try to disable the caching of disk writes in
            hardware caches.
      </p>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flush_method">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155282368">
     </a>
     <a class="indexterm" name="idm46045155281328">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flush_method">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flush-method=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
            innodb_flush_method
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value (Unix)
         </th>
         <td>
          <code class="literal">
           O_DIRECT if supported, otherwise fsync
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Default Value (Windows)
         </th>
         <td>
          <code class="literal">
           unbuffered
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values (Unix)
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            fsync
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            O_DSYNC
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            littlesync
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            nosync
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            O_DIRECT
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            O_DIRECT_NO_FSYNC
           </code>
          </p>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values (Windows)
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            unbuffered
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            normal
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the method used to
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flush
      </a>
      data to
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_data_files" title="data files">
       data
          files
      </a>
      and
      <a class="link" href="glossary.html#glos_log_file" title="log file">
       log
          files
      </a>
      , which can affect I/O throughput.
     </p>
     <p>
      On Unix-like systems, the default value is
      <code class="literal">
       O_DIRECT
      </code>
      if supported otherwise defaults to
      <code class="literal">
       fsync
      </code>
      . On Windows, the default value is
      <code class="literal">
       unbuffered
      </code>
      .
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
      options for Unix-like systems include:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         <code class="literal">
          fsync
         </code>
         or
         <code class="literal">
          0
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses the
         <code class="literal">
          fsync()
         </code>
         system call to flush both the
              data and log files.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          O_DSYNC
         </code>
         or
         <code class="literal">
          1
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses
         <code class="literal">
          O_SYNC
         </code>
         to open and flush the log files, and
         <code class="literal">
          fsync()
         </code>
         to flush the data files.
         <code class="literal">
          InnoDB
         </code>
         does not use
         <code class="literal">
          O_DSYNC
         </code>
         directly because there have
              been problems with it on many varieties of Unix.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          littlesync
         </code>
         or
         <code class="literal">
          2
         </code>
         :
              This option is used for internal performance testing and
              is currently unsupported. Use at your own risk.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          nosync
         </code>
         or
         <code class="literal">
          3
         </code>
         : This
              option is used for internal performance testing and is
              currently unsupported. Use at your own risk.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          O_DIRECT
         </code>
         or
         <code class="literal">
          4
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses
         <code class="literal">
          O_DIRECT
         </code>
         (or
         <code class="literal">
          directio()
         </code>
         on Solaris) to open the
              data files, and uses
         <code class="literal">
          fsync()
         </code>
         to flush
              both the data and log files. This option is available on
              some GNU/Linux versions, FreeBSD, and Solaris.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          O_DIRECT_NO_FSYNC
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses
         <code class="literal">
          O_DIRECT
         </code>
         during flushing I/O, but skips the
         <code class="literal">
          fsync()
         </code>
         system call after each write
              operation.
        </p>
        <p>
         MySQL calls
         <code class="literal">
          fsync()
         </code>
         after creating a
              new file, after increasing file size, and after closing a
              file, to ensure that file system metadata changes are
              synchronized. The
         <code class="literal">
          fsync()
         </code>
         system call
              is still skipped after each write operation.
        </p>
        <p>
         Data loss is possible if redo log files and data files
              reside on different storage devices, and an unexpected
              exit occurs before data file writes are flushed from a
              device cache that is not battery-backed. If you use or
              intend to use different storage devices for redo log files
              and data files, and your data files reside on a device
              with a cache that is not battery-backed, use
         <code class="literal">
          O_DIRECT
         </code>
         instead.
        </p>
       </li>
      </ul>
     </div>
     <p>
      On platforms that support
      <code class="literal">
       fdatasync()
      </code>
      system calls, the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
       <code class="literal">
        innodb_use_fdatasync
       </code>
      </a>
      variable
          permits
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
      options that use
      <code class="literal">
       fsync()
      </code>
      to use
      <code class="literal">
       fdatasync()
      </code>
      instead. An
      <code class="literal">
       fdatasync()
      </code>
      system call does not flush
          changes to file metadata unless required for subsequent data
          retrieval, providing a potential performance benefit.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
      options for Windows systems include:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         <code class="literal">
          unbuffered
         </code>
         or
         <code class="literal">
          0
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses non-buffered I/O.
        </p>
        <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
         <div class="admon-title">
          Note
         </div>
         <p>
          Running MySQL server on a 4K sector hard drive on
                Windows is not supported with
          <code class="literal">
           unbuffered
          </code>
          . The workaround is to use
          <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
           <code class="literal">
            innodb_flush_method=normal
           </code>
          </a>
          .
         </p>
        </div>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          normal
         </code>
         or
         <code class="literal">
          1
         </code>
         :
         <code class="literal">
          InnoDB
         </code>
         uses buffered I/O.
        </p>
       </li>
      </ul>
     </div>
     <p>
      How each setting affects performance depends on hardware
          configuration and workload. Benchmark your particular
          configuration to decide which setting to use, or whether to
          keep the default setting. Examine the
      <a class="link" href="server-status-variables.html#statvar_Innodb_data_fsyncs">
       <code class="literal">
        Innodb_data_fsyncs
       </code>
      </a>
      status
          variable to see the overall number of
      <code class="literal">
       fsync()
      </code>
      calls (or
      <code class="literal">
       fdatasync()
      </code>
      calls if
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
       <code class="literal">
        innodb_use_fdatasync
       </code>
      </a>
      is
          enabled) for each setting. The mix of read and write
          operations in your workload can affect how a setting performs.
          For example, on a system with a hardware RAID controller and
          battery-backed write cache,
      <code class="literal">
       O_DIRECT
      </code>
      can
          help to avoid double buffering between the
      <code class="literal">
       InnoDB
      </code>
      buffer pool and the operating system
          file system cache. On some systems where
      <code class="literal">
       InnoDB
      </code>
      data and log files are located on a
          SAN, the default value or
      <code class="literal">
       O_DSYNC
      </code>
      might be
          faster for a read-heavy workload with mostly
      <code class="literal">
       SELECT
      </code>
      statements. Always test this
          parameter with hardware and workload that reflect your
          production environment. For general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flush_neighbors">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_neighbors">
       <code class="literal">
        innodb_flush_neighbors
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155180336">
     </a>
     <a class="indexterm" name="idm46045155179296">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flush_neighbors">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flush-neighbors=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_neighbors">
            innodb_flush_neighbors
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            0
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            1
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            2
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies whether
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flushing
      </a>
      a
          page from the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      also
          flushes other
      <a class="link" href="glossary.html#glos_dirty_page" title="dirty page">
       dirty
          pages
      </a>
      in the same
      <a class="link" href="glossary.html#glos_extent" title="extent">
       extent
      </a>
      .
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         A setting of 0 disables
         <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_neighbors">
          <code class="literal">
           innodb_flush_neighbors
          </code>
         </a>
         .
              Dirty pages in the same extent are not flushed.
        </p>
       </li>
       <li class="listitem">
        <p>
         A setting of 1 flushes contiguous dirty pages in the same
              extent.
        </p>
       </li>
       <li class="listitem">
        <p>
         A setting of 2 flushes dirty pages in the same extent.
        </p>
       </li>
      </ul>
     </div>
     <p>
      When the table data is stored on a traditional
      <a class="link" href="glossary.html#glos_hdd" title="HDD">
       HDD
      </a>
      storage device, flushing
          such
      <a class="link" href="glossary.html#glos_neighbor_page" title="neighbor page">
       neighbor pages
      </a>
      in one operation reduces I/O overhead (primarily for disk seek
          operations) compared to flushing individual pages at different
          times. For table data stored on
      <a class="link" href="glossary.html#glos_ssd" title="SSD">
       SSD
      </a>
      , seek time is not a
          significant factor and you can set this option to 0 to spread
          out write operations. For related information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flush_sync">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
       <code class="literal">
        innodb_flush_sync
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155137568">
     </a>
     <a class="indexterm" name="idm46045155136528">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flush_sync">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flush-sync[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
            innodb_flush_sync
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
       <code class="literal">
        innodb_flush_sync
       </code>
      </a>
      variable, which is enabled by default, causes the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
       <code class="literal">
        innodb_io_capacity_max
       </code>
      </a>
      settings to be ignored during bursts of I/O activity that
          occur at
      <a class="link" href="glossary.html#glos_checkpoint" title="checkpoint">
       checkpoints
      </a>
      .
          To adhere to the I/O rate defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
       <code class="literal">
        innodb_io_capacity_max
       </code>
      </a>
      ,
          disable
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
       <code class="literal">
        innodb_flush_sync
       </code>
      </a>
      .
     </p>
     <p>
      For information about configuring the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
       <code class="literal">
        innodb_flush_sync
       </code>
      </a>
      variable,
          see
      <a class="xref" href="innodb-configuring-io-capacity.html" title="17.8.7 Configuring InnoDB I/O Capacity">
       Section 17.8.7, “Configuring InnoDB I/O Capacity”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_flushing_avg_loops">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flushing_avg_loops">
       <code class="literal">
        innodb_flushing_avg_loops
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155100960">
     </a>
     <a class="indexterm" name="idm46045155099856">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_flushing_avg_loops">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-flushing-avg-loops=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_flushing_avg_loops">
            innodb_flushing_avg_loops
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           30
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Number of iterations for which
      <code class="literal">
       InnoDB
      </code>
      keeps
          the previously calculated snapshot of the flushing state,
          controlling how quickly
      <a class="link" href="glossary.html#glos_adaptive_flushing" title="adaptive flushing">
       adaptive
          flushing
      </a>
      responds to changing
      <a class="link" href="glossary.html#glos_workload" title="workload">
       workloads
      </a>
      . Increasing the
          value makes the rate of
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flush
      </a>
      operations change
          smoothly and gradually as the workload changes. Decreasing the
          value makes adaptive flushing adjust quickly to workload
          changes, which can cause spikes in flushing activity if the
          workload increases and decreases suddenly.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_force_load_corrupted">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_force_load_corrupted">
       <code class="literal">
        innodb_force_load_corrupted
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155065568">
     </a>
     <a class="indexterm" name="idm46045155064464">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_force_load_corrupted">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-force-load-corrupted[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_force_load_corrupted">
            innodb_force_load_corrupted
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Permits
      <code class="literal">
       InnoDB
      </code>
      to load tables at startup
          that are marked as corrupted. Use only during troubleshooting,
          to recover data that is otherwise inaccessible. When
          troubleshooting is complete, disable this setting and restart
          the server.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_force_recovery">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
       <code class="literal">
        innodb_force_recovery
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045155038864">
     </a>
     <a class="indexterm" name="idm46045155037824">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_force_recovery">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-force-recovery=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
            innodb_force_recovery
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           6
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="glossary.html#glos_crash_recovery" title="crash recovery">
       crash recovery
      </a>
      mode, typically only changed in serious troubleshooting
          situations. Possible values are from 0 to 6. For the meanings
          of these values and important information about
      <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
       <code class="literal">
        innodb_force_recovery
       </code>
      </a>
      , see
      <a class="xref" href="forcing-innodb-recovery.html" title="17.20.3 Forcing InnoDB Recovery">
       Section 17.20.3, “Forcing InnoDB Recovery”
      </a>
      .
     </p>
     <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Warning
      </div>
      <p>
       Only set this variable to a value greater than 0 in an
            emergency situation so that you can start
       <code class="literal">
        InnoDB
       </code>
       and dump your tables. As a safety
            measure,
       <code class="literal">
        InnoDB
       </code>
       prevents
       <a class="link" href="insert.html" title="15.2.7 INSERT Statement">
        <code class="literal">
         INSERT
        </code>
       </a>
       ,
       <a class="link" href="update.html" title="15.2.17 UPDATE Statement">
        <code class="literal">
         UPDATE
        </code>
       </a>
       , or
       <a class="link" href="delete.html" title="15.2.2 DELETE Statement">
        <code class="literal">
         DELETE
        </code>
       </a>
       operations when
       <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
        <code class="literal">
         innodb_force_recovery
        </code>
       </a>
       is
            greater than 0. An
       <a class="link" href="innodb-parameters.html#sysvar_innodb_force_recovery">
        <code class="literal">
         innodb_force_recovery
        </code>
       </a>
       setting of 4 or greater places
       <code class="literal">
        InnoDB
       </code>
       into read-only mode.
      </p>
      <p>
       These restrictions may cause replication administration
            commands to fail with an error, as replication stores the
            replica status logs in
       <code class="literal">
        InnoDB
       </code>
       tables.
      </p>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_fsync_threshold">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fsync_threshold">
       <code class="literal">
        innodb_fsync_threshold
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154994720">
     </a>
     <a class="indexterm" name="idm46045154993680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_fsync_threshold">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-fsync-threshold=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_fsync_threshold">
            innodb_fsync_threshold
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      By default, when
      <code class="literal">
       InnoDB
      </code>
      creates a new data
          file, such as a new log file or tablespace file, the file is
          fully written to the operating system cache before it is
          flushed to disk, which can cause a large amount of disk write
          activity to occur at once. To force smaller, periodic flushes
          of data from the operating system cache, you can use the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fsync_threshold">
       <code class="literal">
        innodb_fsync_threshold
       </code>
      </a>
      variable to define a threshold value, in bytes. When the byte
          threshold is reached, the contents of the operating system
          cache are flushed to disk. The default value of 0 forces the
          default behavior, which is to flush data to disk only after a
          file is fully written to the cache.
     </p>
     <p>
      Specifying a threshold to force smaller, periodic flushes may
          be beneficial in cases where multiple MySQL instances use the
          same storage devices. For example, creating a new MySQL
          instance and its associated data files could cause large
          surges of disk write activity, impeding the performance of
          other MySQL instances that use the same storage devices.
          Configuring a threshold helps avoid such surges in write
          activity.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_aux_table">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_aux_table">
       <code class="literal">
        innodb_ft_aux_table
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154960656">
     </a>
     <a class="indexterm" name="idm46045154959616">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_aux_table">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_aux_table">
            innodb_ft_aux_table
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the qualified name of an
      <code class="literal">
       InnoDB
      </code>
      table containing a
      <code class="literal">
       FULLTEXT
      </code>
      index. This
          variable is intended for diagnostic purposes and can only be
          set at runtime. For example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa51050869"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> innodb_ft_aux_table <span class="token operator">=</span> <span class="token string">'test/t1'</span><span class="token punctuation">;</span></code></pre>
     </div>
     <p>
      After you set this variable to a name in the format
      <code class="literal">
       <em class="replaceable">
        <code>
         db_name
        </code>
       </em>
       /
       <em class="replaceable">
        <code>
         table_name
        </code>
       </em>
      </code>
      ,
          the
      <code class="literal">
       INFORMATION_SCHEMA
      </code>
      tables
      <a class="link" href="information-schema-innodb-ft-index-table-table.html" title="28.4.19 The INFORMATION_SCHEMA INNODB_FT_INDEX_TABLE Table">
       <code class="literal">
        INNODB_FT_INDEX_TABLE
       </code>
      </a>
      ,
      <a class="link" href="information-schema-innodb-ft-index-cache-table.html" title="28.4.18 The INFORMATION_SCHEMA INNODB_FT_INDEX_CACHE Table">
       <code class="literal">
        INNODB_FT_INDEX_CACHE
       </code>
      </a>
      ,
      <a class="link" href="information-schema-innodb-ft-config-table.html" title="28.4.15 The INFORMATION_SCHEMA INNODB_FT_CONFIG Table">
       <code class="literal">
        INNODB_FT_CONFIG
       </code>
      </a>
      ,
      <a class="link" href="information-schema-innodb-ft-deleted-table.html" title="28.4.17 The INFORMATION_SCHEMA INNODB_FT_DELETED Table">
       <code class="literal">
        INNODB_FT_DELETED
       </code>
      </a>
      , and
      <a class="link" href="information-schema-innodb-ft-being-deleted-table.html" title="28.4.14 The INFORMATION_SCHEMA INNODB_FT_BEING_DELETED Table">
       <code class="literal">
        INNODB_FT_BEING_DELETED
       </code>
      </a>
      show
          information about the search index for the specified table.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-information-schema-fulltext_index-tables.html" title="17.15.4 InnoDB INFORMATION_SCHEMA FULLTEXT Index Tables">
       Section 17.15.4, “InnoDB INFORMATION_SCHEMA FULLTEXT Index Tables”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_cache_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_cache_size">
       <code class="literal">
        innodb_ft_cache_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154927184">
     </a>
     <a class="indexterm" name="idm46045154926144">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_cache_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-cache-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_cache_size">
            innodb_ft_cache_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           8000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1600000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           80000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The memory allocated, in bytes, for the
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      search
          index cache, which holds a parsed document in memory while
          creating an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index. Index inserts and updates
          are only committed to disk when the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_cache_size">
       <code class="literal">
        innodb_ft_cache_size
       </code>
      </a>
      size
          limit is reached.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_cache_size">
       <code class="literal">
        innodb_ft_cache_size
       </code>
      </a>
      defines
          the cache size on a per table basis. To set a global limit for
          all tables, see
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_total_cache_size">
       <code class="literal">
        innodb_ft_total_cache_size
       </code>
      </a>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-fulltext-index.html#innodb-fulltext-index-cache" title="InnoDB Full-Text Index Cache">
       InnoDB Full-Text Index Cache
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_enable_diag_print">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_diag_print">
       <code class="literal">
        innodb_ft_enable_diag_print
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154886528">
     </a>
     <a class="indexterm" name="idm46045154885424">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_enable_diag_print">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-enable-diag-print[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_diag_print">
            innodb_ft_enable_diag_print
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Whether to enable additional full-text search (FTS) diagnostic
          output. This option is primarily intended for advanced FTS
          debugging and is not of interest to most users. Output is
          printed to the error log and includes information such as:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         FTS index sync progress (when the FTS cache limit is
              reached). For example:
        </p>
        <div class="copytoclipboard-wrapper">
         <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa84819959"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">FTS SYNC for table test<span class="token punctuation">,</span> deleted count<span class="token punctuation">:</span> 100 size<span class="token punctuation">:</span> 10000 bytes
SYNC words<span class="token punctuation">:</span> 100</code></pre>
        </div>
       </li>
       <li class="listitem">
        <p>
         FTS optimize progress. For example:
        </p>
        <div class="copytoclipboard-wrapper">
         <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa19082731"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">FTS start optimize test
FTS_OPTIMIZE<span class="token punctuation">:</span> optimize <span class="token atrule">"mysql"</span>
FTS_OPTIMIZE<span class="token punctuation">:</span> processed <span class="token atrule">"mysql"</span></code></pre>
        </div>
       </li>
       <li class="listitem">
        <p>
         FTS index build progress. For example:
        </p>
        <div class="copytoclipboard-wrapper">
         <pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa92060829"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">Number of doc processed<span class="token punctuation">:</span> 1000</code></pre>
        </div>
       </li>
       <li class="listitem">
        <p>
         For FTS queries, the query parsing tree, word weight,
              query processing time, and memory usage are printed. For
              example:
        </p>
        <div class="copytoclipboard-wrapper">
         <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa44572851"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">FTS Search Processing time<span class="token punctuation">:</span> 1 secs<span class="token punctuation">:</span> 100 millisec<span class="token punctuation">:</span> row<span class="token punctuation">(</span>s<span class="token punctuation">)</span> 10000
Full Search Memory<span class="token punctuation">:</span> 245666 <span class="token punctuation">(</span>bytes<span class="token punctuation">)</span><span class="token punctuation">,</span>  Row<span class="token punctuation">:</span> 10000</code></pre>
        </div>
       </li>
      </ul>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_enable_stopword">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_stopword">
       <code class="literal">
        innodb_ft_enable_stopword
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154852544">
     </a>
     <a class="indexterm" name="idm46045154851440">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_enable_stopword">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-enable-stopword[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_stopword">
            innodb_ft_enable_stopword
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies that a set of
      <a class="link" href="glossary.html#glos_stopword" title="stopword">
       stopwords
      </a>
      is associated
          with an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index at the time the index is created. If the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
      option is set, the stopwords are taken from that table. Else,
          if the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
      option is set, the stopwords are taken from that table.
          Otherwise, a built-in set of default stopwords is used.
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-stopwords.html" title="14.9.4 Full-Text Stopwords">
       Section 14.9.4, “Full-Text Stopwords”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_max_token_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_max_token_size">
       <code class="literal">
        innodb_ft_max_token_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154820528">
     </a>
     <a class="indexterm" name="idm46045154819424">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_max_token_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-max-token-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_max_token_size">
            innodb_ft_max_token_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           84
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           10
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           84
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Maximum character length of words that are stored in an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index.
          Setting a limit on this value reduces the size of the index,
          thus speeding up queries, by omitting long keywords or
          arbitrary collections of letters that are not real words and
          are not likely to be search terms.
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-fine-tuning.html" title="14.9.6 Fine-Tuning MySQL Full-Text Search">
       Section 14.9.6, “Fine-Tuning MySQL Full-Text Search”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_min_token_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_min_token_size">
       <code class="literal">
        innodb_ft_min_token_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154787184">
     </a>
     <a class="indexterm" name="idm46045154786080">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_min_token_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-min-token-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_min_token_size">
            innodb_ft_min_token_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           3
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           16
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Minimum length of words that are stored in an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index.
          Increasing this value reduces the size of the index, thus
          speeding up queries, by omitting common words that are
          unlikely to be significant in a search context, such as the
          English words
      <span class="quote">
       “
       <span class="quote">
        a
       </span>
       ”
      </span>
      and
      <span class="quote">
       “
       <span class="quote">
        to
       </span>
       ”
      </span>
      . For
          content using a CJK (Chinese, Japanese, Korean) character set,
          specify a value of 1.
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-fine-tuning.html" title="14.9.6 Fine-Tuning MySQL Full-Text Search">
       Section 14.9.6, “Fine-Tuning MySQL Full-Text Search”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_num_word_optimize">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_num_word_optimize">
       <code class="literal">
        innodb_ft_num_word_optimize
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154752960">
     </a>
     <a class="indexterm" name="idm46045154751856">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_num_word_optimize">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-num-word-optimize=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_num_word_optimize">
            innodb_ft_num_word_optimize
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           10000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Number of words to process during each
      <a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
       <code class="literal">
        OPTIMIZE TABLE
       </code>
      </a>
      operation on an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index.
          Because a bulk insert or update operation to a table
          containing a full-text search index could require substantial
          index maintenance to incorporate all changes, you might do a
          series of
      <a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
       <code class="literal">
        OPTIMIZE TABLE
       </code>
      </a>
      statements, each picking up where the last left off.
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-fine-tuning.html" title="14.9.6 Fine-Tuning MySQL Full-Text Search">
       Section 14.9.6, “Fine-Tuning MySQL Full-Text Search”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_result_cache_limit">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_result_cache_limit">
       <code class="literal">
        innodb_ft_result_cache_limit
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154717008">
     </a>
     <a class="indexterm" name="idm46045154715904">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_result_cache_limit">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-result-cache-limit=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_result_cache_limit">
            innodb_ft_result_cache_limit
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2000000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <code class="literal">
       InnoDB
      </code>
      full-text search query result
          cache limit (defined in bytes) per full-text search query or
          per thread. Intermediate and final
      <code class="literal">
       InnoDB
      </code>
      full-text search query results are handled in memory. Use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_result_cache_limit">
       <code class="literal">
        innodb_ft_result_cache_limit
       </code>
      </a>
      to place a size limit on the full-text search query result
          cache to avoid excessive memory consumption in case of very
          large
      <code class="literal">
       InnoDB
      </code>
      full-text search query results
          (millions or hundreds of millions of rows, for example).
          Memory is allocated as required when a full-text search query
          is processed. If the result cache size limit is reached, an
          error is returned indicating that the query exceeds the
          maximum allowed memory.
     </p>
     <p>
      The maximum value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_result_cache_limit">
       <code class="literal">
        innodb_ft_result_cache_limit
       </code>
      </a>
      for all platform types and bit sizes is 2**32-1.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_server_stopword_table">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154678464">
     </a>
     <a class="indexterm" name="idm46045154677360">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_server_stopword_table">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-server-stopword-table=db_name/table_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
            innodb_ft_server_stopword_table
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This option is used to specify your own
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index
          stopword list for all
      <code class="literal">
       InnoDB
      </code>
      tables. To
          configure your own stopword list for a specific
      <code class="literal">
       InnoDB
      </code>
      table, use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
      .
     </p>
     <p>
      Set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
      to the name of the table containing a list of stopwords, in
          the format
      <code class="literal">
       <em class="replaceable">
        <code>
         db_name
        </code>
       </em>
       /
       <em class="replaceable">
        <code>
         table_name
        </code>
       </em>
      </code>
      .
     </p>
     <p>
      The stopword table must exist before you configure
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
      .
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_stopword">
       <code class="literal">
        innodb_ft_enable_stopword
       </code>
      </a>
      must be enabled and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
      option must be configured before you create the
      <code class="literal">
       FULLTEXT
      </code>
      index.
     </p>
     <p>
      The stopword table must be an
      <code class="literal">
       InnoDB
      </code>
      table,
          containing a single
      <code class="literal">
       VARCHAR
      </code>
      column named
      <code class="literal">
       value
      </code>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-stopwords.html" title="14.9.4 Full-Text Stopwords">
       Section 14.9.4, “Full-Text Stopwords”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_sort_pll_degree">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_sort_pll_degree">
       <code class="literal">
        innodb_ft_sort_pll_degree
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154636544">
     </a>
     <a class="indexterm" name="idm46045154635440">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_sort_pll_degree">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-sort-pll-degree=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_sort_pll_degree">
            innodb_ft_sort_pll_degree
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           16
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Number of threads used in parallel to index and tokenize text
          in an
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index when building a
      <a class="link" href="glossary.html#glos_search_index" title="search index">
       search
          index
      </a>
      .
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-fulltext-index.html" title="17.6.2.4 InnoDB Full-Text Indexes">
       Section 17.6.2.4, “InnoDB Full-Text Indexes”
      </a>
      , and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sort_buffer_size">
       <code class="literal">
        innodb_sort_buffer_size
       </code>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_total_cache_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_total_cache_size">
       <code class="literal">
        innodb_ft_total_cache_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154601200">
     </a>
     <a class="indexterm" name="idm46045154600096">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_total_cache_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-total-cache-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_total_cache_size">
            innodb_ft_total_cache_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           640000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           32000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1600000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The total memory allocated, in bytes, for the
      <code class="literal">
       InnoDB
      </code>
      full-text search index cache for all
          tables. Creating numerous tables, each with a
      <code class="literal">
       FULLTEXT
      </code>
      search index, could consume a
          significant portion of available memory.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_total_cache_size">
       <code class="literal">
        innodb_ft_total_cache_size
       </code>
      </a>
      defines a global memory limit for all full-text search indexes
          to help avoid excessive memory consumption. If the global
          limit is reached by an index operation, a forced sync is
          triggered.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-fulltext-index.html#innodb-fulltext-index-cache" title="InnoDB Full-Text Index Cache">
       InnoDB Full-Text Index Cache
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_ft_user_stopword_table">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154564224">
     </a>
     <a class="indexterm" name="idm46045154563120">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_ft_user_stopword_table">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-ft-user-stopword-table=db_name/table_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
            innodb_ft_user_stopword_table
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This option is used to specify your own
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      index
          stopword list on a specific table. To configure your own
          stopword list for all
      <code class="literal">
       InnoDB
      </code>
      tables, use
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_server_stopword_table">
       <code class="literal">
        innodb_ft_server_stopword_table
       </code>
      </a>
      .
     </p>
     <p>
      Set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
      to the name of the table containing a list of stopwords, in
          the format
      <code class="literal">
       <em class="replaceable">
        <code>
         db_name
        </code>
       </em>
       /
       <em class="replaceable">
        <code>
         table_name
        </code>
       </em>
      </code>
      .
     </p>
     <p>
      The stopword table must exist before you configure
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
      .
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_enable_stopword">
       <code class="literal">
        innodb_ft_enable_stopword
       </code>
      </a>
      must be enabled and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_ft_user_stopword_table">
       <code class="literal">
        innodb_ft_user_stopword_table
       </code>
      </a>
      must be configured before you create the
      <code class="literal">
       FULLTEXT
      </code>
      index.
     </p>
     <p>
      The stopword table must be an
      <code class="literal">
       InnoDB
      </code>
      table,
          containing a single
      <code class="literal">
       VARCHAR
      </code>
      column named
      <code class="literal">
       value
      </code>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="fulltext-stopwords.html" title="14.9.4 Full-Text Stopwords">
       Section 14.9.4, “Full-Text Stopwords”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_idle_flush_pct">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_idle_flush_pct">
       <code class="literal">
        innodb_idle_flush_pct
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154522976">
     </a>
     <a class="indexterm" name="idm46045154521936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_idle_flush_pct">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-idle-flush-pct=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_idle_flush_pct">
            innodb_idle_flush_pct
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Limits page flushing when
      <code class="literal">
       InnoDB
      </code>
      is idle.
          The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_idle_flush_pct">
       <code class="literal">
        innodb_idle_flush_pct
       </code>
      </a>
      value is a percentage of the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      setting,
          which defines the number of I/O operations per second
          available to
      <code class="literal">
       InnoDB
      </code>
      . For more information,
          see
      <a class="xref" href="innodb-buffer-pool-flushing.html#innodb-limit-flushing-rate" title="Limiting Buffer Flushing During Idle Periods">
       Limiting Buffer Flushing During Idle Periods
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_io_capacity">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154487648">
     </a>
     <a class="indexterm" name="idm46045154486608">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_io_capacity">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-io-capacity=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
            innodb_io_capacity
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           10000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value (64-bit platforms, 8.4.0)
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      variable defines the number of I/O operations per second
          (IOPS) available to
      <code class="literal">
       InnoDB
      </code>
      background
          tasks, such as
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flushing
      </a>
      pages from the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer
          pool
      </a>
      and merging data from the
      <a class="link" href="glossary.html#glos_change_buffer" title="change buffer">
       change buffer
      </a>
      .
     </p>
     <p>
      For information about configuring the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      variable,
          see
      <a class="xref" href="innodb-configuring-io-capacity.html" title="17.8.7 Configuring InnoDB I/O Capacity">
       Section 17.8.7, “Configuring InnoDB I/O Capacity”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_io_capacity_max">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
       <code class="literal">
        innodb_io_capacity_max
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154447648">
     </a>
     <a class="indexterm" name="idm46045154446608">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_io_capacity_max">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-io-capacity-max=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
            innodb_io_capacity_max
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2 * innodb_io_capacity
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      If flushing activity falls behind,
      <code class="literal">
       InnoDB
      </code>
      can flush more aggressively, at a higher rate of I/O
          operations per second (IOPS) than defined by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      variable.
          The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
       <code class="literal">
        innodb_io_capacity_max
       </code>
      </a>
      variable defines a maximum number of IOPS performed by
      <code class="literal">
       InnoDB
      </code>
      background tasks in such situations.
          This option does not control
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_sync">
       <code class="literal">
        innodb_flush_sync
       </code>
      </a>
      behavior.
     </p>
     <p>
      The default value is twice the value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity">
       <code class="literal">
        innodb_io_capacity
       </code>
      </a>
      .
     </p>
     <p>
      For information about configuring the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_io_capacity_max">
       <code class="literal">
        innodb_io_capacity_max
       </code>
      </a>
      variable, see
      <a class="xref" href="innodb-configuring-io-capacity.html" title="17.8.7 Configuring InnoDB I/O Capacity">
       Section 17.8.7, “Configuring InnoDB I/O Capacity”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_limit_optimistic_insert_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_limit_optimistic_insert_debug">
       <code class="literal">
        innodb_limit_optimistic_insert_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154407360">
     </a>
     <a class="indexterm" name="idm46045154406272">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_limit_optimistic_insert_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-limit-optimistic-insert-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_limit_optimistic_insert_debug">
            innodb_limit_optimistic_insert_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Limits the number of records per
      <a class="link" href="glossary.html#glos_b_tree" title="B-tree">
       B-tree
      </a>
      page. A default
          value of 0 means that no limit is imposed. This option is only
          available if debugging support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_lock_wait_timeout">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154374192">
     </a>
     <a class="indexterm" name="idm46045154373088">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_lock_wait_timeout">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-lock-wait-timeout=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
            innodb_lock_wait_timeout
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1073741824
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          seconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The length of time in seconds an
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_transaction" title="transaction">
       transaction
      </a>
      waits for
          a
      <a class="link" href="glossary.html#glos_row_lock" title="row lock">
       row lock
      </a>
      before giving
          up. The default value is 50 seconds. A transaction that tries
          to access a row that is locked by another
      <code class="literal">
       InnoDB
      </code>
      transaction waits at most this many
          seconds for write access to the row before issuing the
          following error:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa55581655"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token output">ERROR 1205 (HY000)<span class="token punctuation">:</span> Lock wait timeout exceeded; try restarting transaction</span></code></pre>
     </div>
     <p>
      When a lock wait timeout occurs, the current statement is
      <a class="link" href="glossary.html#glos_rollback" title="rollback">
       rolled back
      </a>
      (not the
          entire transaction). To have the entire transaction roll back,
          start the server with the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_on_timeout">
       <code class="option">
        --innodb-rollback-on-timeout
       </code>
      </a>
      option. See also
      <a class="xref" href="innodb-error-handling.html" title="17.20.5 InnoDB Error Handling">
       Section 17.20.5, “InnoDB Error Handling”
      </a>
      .
     </p>
     <p>
      You might decrease this value for highly interactive
          applications or
      <a class="link" href="glossary.html#glos_oltp" title="OLTP">
       OLTP
      </a>
      systems,
          to display user feedback quickly or put the update into a
          queue for processing later. You might increase this value for
          long-running back-end operations, such as a transform step in
          a data warehouse that waits for other large insert or update
          operations to finish.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
      applies to
      <code class="literal">
       InnoDB
      </code>
      row locks. A MySQL
      <a class="link" href="glossary.html#glos_table_lock" title="table lock">
       table lock
      </a>
      does not
          happen inside
      <code class="literal">
       InnoDB
      </code>
      and this timeout does
          not apply to waits for table locks.
     </p>
     <p>
      The lock wait timeout value does not apply to
      <a class="link" href="glossary.html#glos_deadlock" title="deadlock">
       deadlocks
      </a>
      when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_deadlock_detect">
       <code class="literal">
        innodb_deadlock_detect
       </code>
      </a>
      is
          enabled (the default) because
      <code class="literal">
       InnoDB
      </code>
      detects deadlocks immediately and rolls back one of the
          deadlocked transactions. When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_deadlock_detect">
       <code class="literal">
        innodb_deadlock_detect
       </code>
      </a>
      is
          disabled,
      <code class="literal">
       InnoDB
      </code>
      relies on
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
      for
          transaction rollback when a deadlock occurs. See
      <a class="xref" href="innodb-deadlock-detection.html" title="17.7.5.2 Deadlock Detection">
       Section 17.7.5.2, “Deadlock Detection”
      </a>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
      can
          be set at runtime with the
      <code class="literal">
       SET GLOBAL
      </code>
      or
      <code class="literal">
       SET SESSION
      </code>
      statement. Changing the
      <code class="literal">
       GLOBAL
      </code>
      setting requires privileges
          sufficient to set global system variables (see
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      ) and affects the
          operation of all clients that subsequently connect. Any client
          can change the
      <code class="literal">
       SESSION
      </code>
      setting for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lock_wait_timeout">
       <code class="literal">
        innodb_lock_wait_timeout
       </code>
      </a>
      ,
          which affects only that client.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_buffer_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_buffer_size">
       <code class="literal">
        innodb_log_buffer_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154314160">
     </a>
     <a class="indexterm" name="idm46045154313120">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_buffer_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-buffer-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_buffer_size">
            innodb_log_buffer_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           67108864
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1048576
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The size in bytes of the buffer that
      <code class="literal">
       InnoDB
      </code>
      uses to write to the
      <a class="link" href="glossary.html#glos_log_file" title="log file">
       log
          files
      </a>
      on disk. The default is 64MB. A large
      <a class="link" href="glossary.html#glos_log_buffer" title="log buffer">
       log buffer
      </a>
      enables
          large
      <a class="link" href="glossary.html#glos_transaction" title="transaction">
       transactions
      </a>
      to
          run without the need to write the log to disk before the
          transactions
      <a class="link" href="glossary.html#glos_commit" title="commit">
       commit
      </a>
      . Thus,
          if you have transactions that update, insert, or delete many
          rows, making the log buffer larger saves disk I/O. For related
          information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-memory-configuration" title="Memory Configuration">
       Memory Configuration
      </a>
      , and
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      . For general I/O
          tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_checkpoint_fuzzy_now">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_fuzzy_now">
       <code class="literal">
        innodb_log_checkpoint_fuzzy_now
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154277120">
     </a>
     <a class="indexterm" name="idm46045154276016">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_checkpoint_fuzzy_now">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-checkpoint-fuzzy-now[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_fuzzy_now">
            innodb_log_checkpoint_fuzzy_now
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enable this debug option to force
      <code class="literal">
       InnoDB
      </code>
      to
          write a fuzzy checkpoint. This option is only available if
          debugging support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_checkpoint_now">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_now">
       <code class="literal">
        innodb_log_checkpoint_now
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154248896">
     </a>
     <a class="indexterm" name="idm46045154247792">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_checkpoint_now">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-checkpoint-now[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checkpoint_now">
            innodb_log_checkpoint_now
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enable this debug option to force
      <code class="literal">
       InnoDB
      </code>
      to
          write a checkpoint. This option is only available if debugging
          support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_checksums">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checksums">
       <code class="literal">
        innodb_log_checksums
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154220672">
     </a>
     <a class="indexterm" name="idm46045154219632">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_checksums">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-checksums[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checksums">
            innodb_log_checksums
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables or disables checksums for redo log pages.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checksums">
       <code class="literal">
        innodb_log_checksums=ON
       </code>
      </a>
      enables the
      <code class="literal">
       CRC-32C
      </code>
      checksum algorithm for
          redo log pages. When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_checksums">
       <code class="literal">
        innodb_log_checksums
       </code>
      </a>
      is
          disabled, the contents of the redo log page checksum field are
          ignored.
     </p>
     <p>
      Checksums on the redo log header page and redo log checkpoint
          pages are never disabled.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_compressed_pages">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
       <code class="literal">
        innodb_log_compressed_pages
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154190768">
     </a>
     <a class="indexterm" name="idm46045154189664">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_compressed_pages">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-compressed-pages[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
            innodb_log_compressed_pages
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies whether images of
      <a class="link" href="glossary.html#glos_compression" title="compression">
       re-compressed
      </a>
      <a class="link" href="glossary.html#glos_page" title="page">
       pages
      </a>
      are written to the
      <a class="link" href="glossary.html#glos_redo_log" title="redo log">
       redo log
      </a>
      . Re-compression
          may occur when changes are made to compressed data.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
       <code class="literal">
        innodb_log_compressed_pages
       </code>
      </a>
      is enabled by default to prevent corruption that could occur
          if a different version of the
      <code class="literal">
       zlib
      </code>
      compression algorithm is used during recovery. If you are
          certain that the
      <code class="literal">
       zlib
      </code>
      version is not
          subject to change, you can disable
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
       <code class="literal">
        innodb_log_compressed_pages
       </code>
      </a>
      to reduce redo log generation for workloads that modify
          compressed data.
     </p>
     <p>
      To measure the effect of enabling or disabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_compressed_pages">
       <code class="literal">
        innodb_log_compressed_pages
       </code>
      </a>
      ,
          compare redo log generation for both settings under the same
          workload. Options for measuring redo log generation include
          observing the
      <code class="literal">
       Log sequence number
      </code>
      (LSN) in
          the
      <code class="literal">
       LOG
      </code>
      section of
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB STATUS
       </code>
      </a>
      output, or monitoring
      <a class="link" href="server-status-variables.html#statvar_Innodb_os_log_written">
       <code class="literal">
        Innodb_os_log_written
       </code>
      </a>
      status
          for the number of bytes written to the redo log files.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-performance-compression-oltp.html" title="17.9.1.6 Compression for OLTP Workloads">
       Section 17.9.1.6, “Compression for OLTP Workloads”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_file_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154150720">
     </a>
     <a class="indexterm" name="idm46045154149680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_file_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-file-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Deprecated
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
            innodb_log_file_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50331648
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           4194304
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           512GB / innodb_log_files_in_group
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
        <code class="literal">
         innodb_log_file_size
        </code>
       </a>
       and
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
        <code class="literal">
         innodb_log_files_in_group
        </code>
       </a>
       have been superseded by
       <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
        <code class="literal">
         innodb_redo_log_capacity
        </code>
       </a>
       ;
            see
       <a class="xref" href="innodb-redo-log.html" title="17.6.5 Redo Log">
        Section 17.6.5, “Redo Log”
       </a>
       .
      </p>
     </div>
     <p>
      The size in bytes of each
      <a class="link" href="glossary.html#glos_log_file" title="log file">
       log
          file
      </a>
      in a
      <a class="link" href="glossary.html#glos_log_group" title="log group">
       log
          group
      </a>
      . The combined size of log files
          (
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
       <code class="literal">
        innodb_log_files_in_group
       </code>
      </a>
      )
          cannot exceed a maximum value that is slightly less than
          512GB. A pair of 255 GB log files, for example, approaches the
          limit but does not exceed it. The default value is 48MB.
     </p>
     <p>
      Generally, the combined size of the log files should be large
          enough that the server can smooth out peaks and troughs in
          workload activity, which often means that there is enough redo
          log space to handle more than an hour of write activity. The
          larger the value, the less checkpoint flush activity is
          required in the buffer pool, saving disk I/O. Larger log files
          also make
      <a class="link" href="glossary.html#glos_crash_recovery" title="crash recovery">
       crash
          recovery
      </a>
      slower.
     </p>
     <p>
      The minimum
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
      is 4MB.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-log-file-configuration" title="Redo Log Configuration">
       Redo Log Configuration
      </a>
      . For
          general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
     <p>
      If the server is started with
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
       <code class="option">
        --innodb-dedicated-server
       </code>
      </a>
      , the
          value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
      is set automatically if it is not explicitly defined. For more
          information, see
      <a class="xref" href="innodb-dedicated-server.html" title="17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server">
       Section 17.8.12, “Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_files_in_group">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
       <code class="literal">
        innodb_log_files_in_group
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154097488">
     </a>
     <a class="indexterm" name="idm46045154096384">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_files_in_group">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-files-in-group=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Deprecated
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
            innodb_log_files_in_group
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
        <code class="literal">
         innodb_log_file_size
        </code>
       </a>
       and
       <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
        <code class="literal">
         innodb_log_files_in_group
        </code>
       </a>
       have been superseded by
       <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
        <code class="literal">
         innodb_redo_log_capacity
        </code>
       </a>
       ;
            see
       <a class="xref" href="innodb-redo-log.html" title="17.6.5 Redo Log">
        Section 17.6.5, “Redo Log”
       </a>
       .
      </p>
     </div>
     <p>
      The number of
      <a class="link" href="glossary.html#glos_log_file" title="log file">
       log files
      </a>
      in the
      <a class="link" href="glossary.html#glos_log_group" title="log group">
       log group
      </a>
      .
      <code class="literal">
       InnoDB
      </code>
      writes to the files in a circular
          fashion. The default (and recommended) value is 2. The
          location of the files is specified by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_group_home_dir">
       <code class="literal">
        innodb_log_group_home_dir
       </code>
      </a>
      .
          The combined size of log files
          (
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
       <code class="literal">
        innodb_log_files_in_group
       </code>
      </a>
      )
          can be up to 512GB.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-log-file-configuration" title="Redo Log Configuration">
       Redo Log Configuration
      </a>
      .
     </p>
     <p>
      If the server is started with
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
       <code class="option">
        --innodb-dedicated-server
       </code>
      </a>
      , the
          value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
       <code class="literal">
        innodb_log_files_in_group
       </code>
      </a>
      is
          set automatically if it is not explicitly defined. For more
          information, see
      <a class="xref" href="innodb-dedicated-server.html" title="17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server">
       Section 17.8.12, “Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_group_home_dir">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_group_home_dir">
       <code class="literal">
        innodb_log_group_home_dir
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154048576">
     </a>
     <a class="indexterm" name="idm46045154047472">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_group_home_dir">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-group-home-dir=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_group_home_dir">
            innodb_log_group_home_dir
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The directory path to the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_redo_log" title="redo log">
       redo log
      </a>
      files.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-init-startup-configuration.html#innodb-startup-log-file-configuration" title="Redo Log Configuration">
       Redo Log Configuration
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_spin_cpu_abs_lwm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_abs_lwm">
       <code class="literal">
        innodb_log_spin_cpu_abs_lwm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045154022624">
     </a>
     <a class="indexterm" name="idm46045154021520">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_spin_cpu_abs_lwm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-spin-cpu-abs-lwm=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_abs_lwm">
            innodb_log_spin_cpu_abs_lwm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           80
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the minimum amount of CPU usage below which user
          threads no longer spin while waiting for flushed redo. The
          value is expressed as a sum of CPU core usage. For example,
          The default value of 80 is 80% of a single CPU core. On a
          system with a multi-core processor, a value of 150 represents
          100% usage of one CPU core plus 50% usage of a second CPU
          core.
     </p>
     <p>
      For related information, see
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_spin_cpu_pct_hwm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_pct_hwm">
       <code class="literal">
        innodb_log_spin_cpu_pct_hwm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153990512">
     </a>
     <a class="indexterm" name="idm46045153989408">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_spin_cpu_pct_hwm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-spin-cpu-pct-hwm=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_pct_hwm">
            innodb_log_spin_cpu_pct_hwm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum amount of CPU usage above which user
          threads no longer spin while waiting for flushed redo. The
          value is expressed as a percentage of the combined total
          processing power of all CPU cores. The default value is 50%.
          For example, 100% usage of two CPU cores is 50% of the
          combined CPU processing power on a server with four CPU cores.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_spin_cpu_pct_hwm">
       <code class="literal">
        innodb_log_spin_cpu_pct_hwm
       </code>
      </a>
      variable respects processor affinity. For example, if a server
          has 48 cores but the
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      process is
          pinned to only four CPU cores, the other 44 CPU cores are
          ignored.
     </p>
     <p>
      For related information, see
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_wait_for_flush_spin_hwm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_wait_for_flush_spin_hwm">
       <code class="literal">
        innodb_log_wait_for_flush_spin_hwm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153955184">
     </a>
     <a class="indexterm" name="idm46045153954144">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_wait_for_flush_spin_hwm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-wait-for-flush-spin-hwm=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_wait_for_flush_spin_hwm">
            innodb_log_wait_for_flush_spin_hwm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           400
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value (64-bit platforms, 8.4.0)
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          microseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum average log flush time beyond which user
          threads no longer spin while waiting for flushed redo. The
          default value is 400 microseconds.
     </p>
     <p>
      For related information, see
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_write_ahead_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153918832">
     </a>
     <a class="indexterm" name="idm46045153917728">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_write_ahead_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-write-ahead-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
            innodb_log_write_ahead_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           8192
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           512 (log file block size)
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           Equal to innodb_page_size
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the write-ahead block size for the redo log, in bytes.
          To avoid
      <span class="quote">
       “
       <span class="quote">
        read-on-write
       </span>
       ”
      </span>
      , set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
      to match the operating system or file system cache block size.
          The default setting is 8192 bytes. Read-on-write occurs when
          redo log blocks are not entirely cached to the operating
          system or file system due to a mismatch between write-ahead
          block size for the redo log and operating system or file
          system cache block size.
     </p>
     <p>
      Valid values for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
      are multiples of the
      <code class="literal">
       InnoDB
      </code>
      log file block
          size (2
      <sup>
       n
      </sup>
      ). The minimum value is the
      <code class="literal">
       InnoDB
      </code>
      log file block size (512).
          Write-ahead does not occur when the minimum value is
          specified. The maximum value is equal to the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      value. If
          you specify a value for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
      that is larger than the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      value, the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
      setting is truncated to the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      value.
     </p>
     <p>
      Setting the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_write_ahead_size">
       <code class="literal">
        innodb_log_write_ahead_size
       </code>
      </a>
      value too low in relation to the operating system or file
          system cache block size results in
      <span class="quote">
       “
       <span class="quote">
        read-on-write
       </span>
       ”
      </span>
      . Setting the value too high may
          have a slight impact on
      <code class="literal">
       fsync
      </code>
      performance
          for log file writes due to several blocks being written at
          once.
     </p>
     <p>
      For related information, see
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_log_writer_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_writer_threads">
       <code class="literal">
        innodb_log_writer_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153869616">
     </a>
     <a class="indexterm" name="idm46045153868512">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_log_writer_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-log-writer-threads[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_log_writer_threads">
            innodb_log_writer_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables dedicated log writer threads for writing redo log
          records from the log buffer to the system buffers and flushing
          the system buffers to the redo log files. Dedicated log writer
          threads can improve performance on high-concurrency systems,
          but for low-concurrency systems, disabling dedicated log
          writer threads provides better performance.
     </p>
     <p>
      For more information, see
      <a class="xref" href="optimizing-innodb-logging.html" title="10.5.4 Optimizing InnoDB Redo Logging">
       Section 10.5.4, “Optimizing InnoDB Redo Logging”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_lru_scan_depth">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
       <code class="literal">
        innodb_lru_scan_depth
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153842352">
     </a>
     <a class="indexterm" name="idm46045153841312">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_lru_scan_depth">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-lru-scan-depth=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
            innodb_lru_scan_depth
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1024
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value (64-bit platforms, 8.4.0)
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      A parameter that influences the algorithms and heuristics for
          the
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flush
      </a>
      operation for the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      . Primarily
          of interest to performance experts tuning I/O-intensive
          workloads. It specifies, per buffer pool instance, how far
          down the buffer pool LRU page list the page cleaner thread
          scans looking for
      <a class="link" href="glossary.html#glos_dirty_page" title="dirty page">
       dirty
          pages
      </a>
      to flush. This is a background operation
          performed once per second.
     </p>
     <p>
      A setting smaller than the default is generally suitable for
          most workloads. A value that is much higher than necessary may
          impact performance. Only consider increasing the value if you
          have spare I/O capacity under a typical workload. Conversely,
          if a write-intensive workload saturates your I/O capacity,
          decrease the value, especially in the case of a large buffer
          pool.
     </p>
     <p>
      When tuning
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
       <code class="literal">
        innodb_lru_scan_depth
       </code>
      </a>
      , start
          with a low value and configure the setting upward with the
          goal of rarely seeing zero free pages. Also, consider
          adjusting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
       <code class="literal">
        innodb_lru_scan_depth
       </code>
      </a>
      when
          changing the number of buffer pool instances, since
      <a class="link" href="innodb-parameters.html#sysvar_innodb_lru_scan_depth">
       <code class="literal">
        innodb_lru_scan_depth
       </code>
      </a>
      *
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      defines the amount of work performed by the page cleaner
          thread each second.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      . For general I/O
          tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_max_dirty_pages_pct">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct">
       <code class="literal">
        innodb_max_dirty_pages_pct
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153797312">
     </a>
     <a class="indexterm" name="idm46045153796208">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_max_dirty_pages_pct">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-max-dirty-pages-pct=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct">
            innodb_max_dirty_pages_pct
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Numeric
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           90
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           99.999
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      <code class="literal">
       InnoDB
      </code>
      tries to
      <a class="link" href="glossary.html#glos_flush" title="flush">
       flush
      </a>
      data from the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      so that
          the percentage of
      <a class="link" href="glossary.html#glos_dirty_page" title="dirty page">
       dirty
          pages
      </a>
      does not exceed this value.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct">
       <code class="literal">
        innodb_max_dirty_pages_pct
       </code>
      </a>
      setting establishes a target for flushing activity. It does
          not affect the rate of flushing. For information about
          managing the rate of flushing, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      .
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      . For general I/O
          tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_max_dirty_pages_pct_lwm">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct_lwm">
       <code class="literal">
        innodb_max_dirty_pages_pct_lwm
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153758256">
     </a>
     <a class="indexterm" name="idm46045153757152">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_max_dirty_pages_pct_lwm">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-max-dirty-pages-pct-lwm=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct_lwm">
            innodb_max_dirty_pages_pct_lwm
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Numeric
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           10
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           99.999
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines a low water mark representing the percentage of
      <a class="link" href="glossary.html#glos_dirty_page" title="dirty page">
       dirty pages
      </a>
      at which
          preflushing is enabled to control the dirty page ratio. A
          value of 0 disables the pre-flushing behavior entirely. The
          configured value should always be lower than the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_dirty_pages_pct">
       <code class="literal">
        innodb_max_dirty_pages_pct
       </code>
      </a>
      value. For more information, see
      <a class="xref" href="innodb-buffer-pool-flushing.html" title="17.8.3.5 Configuring Buffer Pool Flushing">
       Section 17.8.3.5, “Configuring Buffer Pool Flushing”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_max_purge_lag">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag">
       <code class="literal">
        innodb_max_purge_lag
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153724560">
     </a>
     <a class="indexterm" name="idm46045153723520">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_max_purge_lag">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-max-purge-lag=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag">
            innodb_max_purge_lag
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the desired maximum purge lag. If this value is
          exceeded, a delay is imposed on
      <a class="link" href="insert.html" title="15.2.7 INSERT Statement">
       <code class="literal">
        INSERT
       </code>
      </a>
      ,
      <a class="link" href="update.html" title="15.2.17 UPDATE Statement">
       <code class="literal">
        UPDATE
       </code>
      </a>
      , and
      <a class="link" href="delete.html" title="15.2.2 DELETE Statement">
       <code class="literal">
        DELETE
       </code>
      </a>
      operations to allow time
          for purge to catch up. The default value is 0, which means
          there is no maximum purge lag and no delay.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-purge-configuration.html" title="17.8.9 Purge Configuration">
       Section 17.8.9, “Purge Configuration”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_max_purge_lag_delay">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag_delay">
       <code class="literal">
        innodb_max_purge_lag_delay
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153689040">
     </a>
     <a class="indexterm" name="idm46045153687936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_max_purge_lag_delay">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-max-purge-lag-delay=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag_delay">
            innodb_max_purge_lag_delay
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           10000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          microseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the maximum delay in microseconds for the delay
          imposed when the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag">
       <code class="literal">
        innodb_max_purge_lag
       </code>
      </a>
      threshold is exceeded. The specified
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag_delay">
       <code class="literal">
        innodb_max_purge_lag_delay
       </code>
      </a>
      value is an upper limit on the delay period calculated by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_purge_lag">
       <code class="literal">
        innodb_max_purge_lag
       </code>
      </a>
      formula.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-purge-configuration.html" title="17.8.9 Purge Configuration">
       Section 17.8.9, “Purge Configuration”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_max_undo_log_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_undo_log_size">
       <code class="literal">
        innodb_max_undo_log_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153651280">
     </a>
     <a class="indexterm" name="idm46045153650176">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_max_undo_log_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-max-undo-log-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_max_undo_log_size">
            innodb_max_undo_log_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1073741824
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           10485760
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines a threshold size for undo tablespaces. If an undo
          tablespace exceeds the threshold, it can be marked for
          truncation when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_truncate">
       <code class="literal">
        innodb_undo_log_truncate
       </code>
      </a>
      is
          enabled. The default value is 1073741824 bytes (1024 MiB).
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-undo-tablespaces.html#truncate-undo-tablespace" title="Truncating Undo Tablespaces">
       Truncating Undo Tablespaces
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_merge_threshold_set_all_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_merge_threshold_set_all_debug">
       <code class="literal">
        innodb_merge_threshold_set_all_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153615856">
     </a>
     <a class="indexterm" name="idm46045153614768">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_merge_threshold_set_all_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-merge-threshold-set-all-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_merge_threshold_set_all_debug">
            innodb_merge_threshold_set_all_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines a page-full percentage value for index pages that
          overrides the current
      <code class="literal">
       MERGE_THRESHOLD
      </code>
      setting for all indexes that are currently in the dictionary
          cache. This option is only available if debugging support is
          compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option. For related information, see
      <a class="xref" href="index-page-merge-threshold.html" title="17.8.11 Configuring the Merge Threshold for Index Pages">
       Section 17.8.11, “Configuring the Merge Threshold for Index Pages”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_monitor_disable">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_disable">
       <code class="literal">
        innodb_monitor_disable
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153582000">
     </a>
     <a class="indexterm" name="idm46045153580960">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_monitor_disable">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-monitor-disable={counter|module|pattern|all}
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_disable">
            innodb_monitor_disable
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable acts as a switch, disabling
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_metrics_counter" title="metrics counter">
       metrics counters
      </a>
      .
          Counter data may be queried using the Information Schema
      <a class="link" href="information-schema-innodb-metrics-table.html" title="28.4.21 The INFORMATION_SCHEMA INNODB_METRICS Table">
       <code class="literal">
        INNODB_METRICS
       </code>
      </a>
      table. For usage
          information, see
      <a class="xref" href="innodb-information-schema-metrics-table.html" title="17.15.6 InnoDB INFORMATION_SCHEMA Metrics Table">
       Section 17.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”
      </a>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_disable">
       <code class="literal">
        innodb_monitor_disable='latch'
       </code>
      </a>
      disables statistics collection for
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB MUTEX
       </code>
      </a>
      . For more information, see
      <a class="xref" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       Section 15.7.7.16, “SHOW ENGINE Statement”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_monitor_enable">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_enable">
       <code class="literal">
        innodb_monitor_enable
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153551408">
     </a>
     <a class="indexterm" name="idm46045153550368">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_monitor_enable">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-monitor-enable={counter|module|pattern|all}
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_enable">
            innodb_monitor_enable
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable acts as a switch, enabling
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_metrics_counter" title="metrics counter">
       metrics counters
      </a>
      .
          Counter data may be queried using the Information Schema
      <a class="link" href="information-schema-innodb-metrics-table.html" title="28.4.21 The INFORMATION_SCHEMA INNODB_METRICS Table">
       <code class="literal">
        INNODB_METRICS
       </code>
      </a>
      table. For usage
          information, see
      <a class="xref" href="innodb-information-schema-metrics-table.html" title="17.15.6 InnoDB INFORMATION_SCHEMA Metrics Table">
       Section 17.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”
      </a>
      .
     </p>
     <p>
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_enable">
       <code class="literal">
        innodb_monitor_enable='latch'
       </code>
      </a>
      enables statistics collection for
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB MUTEX
       </code>
      </a>
      . For more information, see
      <a class="xref" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       Section 15.7.7.16, “SHOW ENGINE Statement”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_monitor_reset">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset">
       <code class="literal">
        innodb_monitor_reset
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153520688">
     </a>
     <a class="indexterm" name="idm46045153519648">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_monitor_reset">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-monitor-reset={counter|module|pattern|all}
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset">
            innodb_monitor_reset
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            counter
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            module
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            pattern
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            all
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable acts as a switch, resetting the count value for
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_metrics_counter" title="metrics counter">
       metrics counters
      </a>
      to zero. Counter data may be queried using the Information
          Schema
      <a class="link" href="information-schema-innodb-metrics-table.html" title="28.4.21 The INFORMATION_SCHEMA INNODB_METRICS Table">
       <code class="literal">
        INNODB_METRICS
       </code>
      </a>
      table. For
          usage information, see
      <a class="xref" href="innodb-information-schema-metrics-table.html" title="17.15.6 InnoDB INFORMATION_SCHEMA Metrics Table">
       Section 17.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”
      </a>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset">
       <code class="literal">
        innodb_monitor_reset='latch'
       </code>
      </a>
      resets statistics reported by
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB MUTEX
       </code>
      </a>
      . For more information, see
      <a class="xref" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       Section 15.7.7.16, “SHOW ENGINE Statement”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_monitor_reset_all">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset_all">
       <code class="literal">
        innodb_monitor_reset_all
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153482096">
     </a>
     <a class="indexterm" name="idm46045153480992">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_monitor_reset_all">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-monitor-reset-all={counter|module|pattern|all}
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_reset_all">
            innodb_monitor_reset_all
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            counter
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            module
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            pattern
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            all
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable acts as a switch, resetting all values (minimum,
          maximum, and so on) for
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_metrics_counter" title="metrics counter">
       metrics counters
      </a>
      .
          Counter data may be queried using the Information Schema
      <a class="link" href="information-schema-innodb-metrics-table.html" title="28.4.21 The INFORMATION_SCHEMA INNODB_METRICS Table">
       <code class="literal">
        INNODB_METRICS
       </code>
      </a>
      table. For usage
          information, see
      <a class="xref" href="innodb-information-schema-metrics-table.html" title="17.15.6 InnoDB INFORMATION_SCHEMA Metrics Table">
       Section 17.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_numa_interleave">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_numa_interleave">
       <code class="literal">
        innodb_numa_interleave
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153446976">
     </a>
     <a class="indexterm" name="idm46045153445936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_numa_interleave">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-numa-interleave[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_numa_interleave">
            innodb_numa_interleave
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables the NUMA interleave memory policy for allocation of
          the
      <code class="literal">
       InnoDB
      </code>
      buffer pool. When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_numa_interleave">
       <code class="literal">
        innodb_numa_interleave
       </code>
      </a>
      is
          enabled, the NUMA memory policy is set to
      <code class="literal">
       MPOL_INTERLEAVE
      </code>
      for the
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      process. After the
      <code class="literal">
       InnoDB
      </code>
      buffer pool is allocated, the NUMA
          memory policy is set back to
      <code class="literal">
       MPOL_DEFAULT
      </code>
      .
          For the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_numa_interleave">
       <code class="literal">
        innodb_numa_interleave
       </code>
      </a>
      option
          to be available, MySQL must be compiled on a NUMA-enabled
          Linux system. The default value is
      <code class="literal">
       ON
      </code>
      if
          the system supports it, otherwise it defaults to
      <code class="literal">
       OFF
      </code>
      .
     </p>
     <p>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      sets the default
      <a class="link" href="source-configuration-options.html#option_cmake_with_numa">
       <code class="option">
        WITH_NUMA
       </code>
      </a>
      value based on whether
          the current platform has
      <code class="literal">
       NUMA
      </code>
      support. For
          more information, see
      <a class="xref" href="source-configuration-options.html" title="2.8.7 MySQL Source-Configuration Options">
       Section 2.8.7, “MySQL Source-Configuration Options”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_old_blocks_pct">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_pct">
       <code class="literal">
        innodb_old_blocks_pct
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153409360">
     </a>
     <a class="indexterm" name="idm46045153408320">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_old_blocks_pct">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-old-blocks-pct=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_pct">
            innodb_old_blocks_pct
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           37
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           5
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           95
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the approximate percentage of the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      used for
          the old block
      <a class="link" href="glossary.html#glos_sublist" title="sublist">
       sublist
      </a>
      . The
          range of values is 5 to 95. The default value is 37 (that is,
          3/8 of the pool). Often used in combination with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_time">
       <code class="literal">
        innodb_old_blocks_time
       </code>
      </a>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-midpoint_insertion.html" title="17.8.3.3 Making the Buffer Pool Scan Resistant">
       Section 17.8.3.3, “Making the Buffer Pool Scan Resistant”
      </a>
      . For
          information about buffer pool management, the
      <a class="link" href="glossary.html#glos_lru" title="LRU">
       LRU
      </a>
      algorithm, and
      <a class="link" href="glossary.html#glos_eviction" title="eviction">
       eviction
      </a>
      policies, see
      <a class="xref" href="innodb-buffer-pool.html" title="17.5.1 Buffer Pool">
       Section 17.5.1, “Buffer Pool”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_old_blocks_time">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_time">
       <code class="literal">
        innodb_old_blocks_time
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153371456">
     </a>
     <a class="indexterm" name="idm46045153370416">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_old_blocks_time">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-old-blocks-time=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_time">
            innodb_old_blocks_time
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          milliseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Non-zero values protect against the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      being
          filled by data that is referenced only for a brief period,
          such as during a
      <a class="link" href="glossary.html#glos_full_table_scan" title="full table scan">
       full
          table scan
      </a>
      . Increasing this value offers more
          protection against full table scans interfering with data
          cached in the buffer pool.
     </p>
     <p>
      Specifies how long in milliseconds a block inserted into the
          old
      <a class="link" href="glossary.html#glos_sublist" title="sublist">
       sublist
      </a>
      must stay
          there after its first access before it can be moved to the new
          sublist. If the value is 0, a block inserted into the old
          sublist moves immediately to the new sublist the first time it
          is accessed, no matter how soon after insertion the access
          occurs. If the value is greater than 0, blocks remain in the
          old sublist until an access occurs at least that many
          milliseconds after the first access. For example, a value of
          1000 causes blocks to stay in the old sublist for 1 second
          after the first access before they become eligible to move to
          the new sublist.
     </p>
     <p>
      The default value is 1000.
     </p>
     <p>
      This variable is often used in combination with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_old_blocks_pct">
       <code class="literal">
        innodb_old_blocks_pct
       </code>
      </a>
      . For
          more information, see
      <a class="xref" href="innodb-performance-midpoint_insertion.html" title="17.8.3.3 Making the Buffer Pool Scan Resistant">
       Section 17.8.3.3, “Making the Buffer Pool Scan Resistant”
      </a>
      . For
          information about buffer pool management, the
      <a class="link" href="glossary.html#glos_lru" title="LRU">
       LRU
      </a>
      algorithm, and
      <a class="link" href="glossary.html#glos_eviction" title="eviction">
       eviction
      </a>
      policies, see
      <a class="xref" href="innodb-buffer-pool.html" title="17.5.1 Buffer Pool">
       Section 17.5.1, “Buffer Pool”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_online_alter_log_max_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_online_alter_log_max_size">
       <code class="literal">
        innodb_online_alter_log_max_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153329728">
     </a>
     <a class="indexterm" name="idm46045153328624">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_online_alter_log_max_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-online-alter-log-max-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_online_alter_log_max_size">
            innodb_online_alter_log_max_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           134217728
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           65536
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**64-1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies an upper limit in bytes on the size of the temporary
          log files used during
      <a class="link" href="glossary.html#glos_online_ddl" title="online DDL">
       online
          DDL
      </a>
      operations for
      <code class="literal">
       InnoDB
      </code>
      tables.
          There is one such log file for each index being created or
          table being altered. This log file stores data inserted,
          updated, or deleted in the table during the DDL operation. The
          temporary log file is extended when needed by the value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sort_buffer_size">
       <code class="literal">
        innodb_sort_buffer_size
       </code>
      </a>
      , up
          to the maximum specified by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_online_alter_log_max_size">
       <code class="literal">
        innodb_online_alter_log_max_size
       </code>
      </a>
      .
          If a temporary log file exceeds the upper size limit, the
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      operation fails and
          all uncommitted concurrent DML operations are rolled back.
          Thus, a large value for this option allows more DML to happen
          during an online DDL operation, but also extends the period of
          time at the end of the DDL operation when the table is locked
          to apply the data from the log.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_open_files">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153290896">
     </a>
     <a class="indexterm" name="idm46045153289856">
     </a>
     <a class="indexterm" name="idm46045153288368">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_open_files">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-open-files=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
            innodb_open_files
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           -1
          </code>
          (signifies autosizing; do not assign this literal value)
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           10
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2147483647
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the maximum number of files that
      <code class="literal">
       InnoDB
      </code>
      can have open at one time. The
          minimum value is 10. If
      <a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
       <code class="literal">
        innodb_file_per_table
       </code>
      </a>
      is
          disabled, the default value is 300; otherwise, the default
          value is 300 or the
      <a class="link" href="server-system-variables.html#sysvar_table_open_cache">
       <code class="literal">
        table_open_cache
       </code>
      </a>
      setting,
          whichever is higher.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files
       </code>
      </a>
      limit
          can be set at runtime using a
      <code class="literal">
       SELECT
          innodb_set_open_files_limit(
       <em class="replaceable">
        <code>
         N
        </code>
       </em>
       )
      </code>
      statement, where
      <em class="replaceable">
       <code>
        N
       </code>
      </em>
      is the desired
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files
       </code>
      </a>
      limit; for
          example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa50026232"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">SELECT</span> innodb_set_open_files_limit<span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
     </div>
     <p>
      The statement executes a stored procedure that sets the new
          limit. If the procedure is successful, it returns the value of
          the newly set limit; otherwise, a failure message is returned.
     </p>
     <p>
      It is not permitted to set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files
       </code>
      </a>
      using a
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
       </code>
      </a>
      statement. To set
      <code class="literal">
       innodb_open_files
      </code>
      at
          runtime, use the
      <code class="literal">
       SELECT
          innodb_set_open_files_limit(
       <em class="replaceable">
        <code>
         N
        </code>
       </em>
       )
      </code>
      statement described above.
     </p>
     <p>
      Setting
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files=default
       </code>
      </a>
      is
          not supported. Only integer values are permitted.
     </p>
     <p>
      To prevent non-LRU managed files from consuming the entire
      <a class="link" href="innodb-parameters.html#sysvar_innodb_open_files">
       <code class="literal">
        innodb_open_files
       </code>
      </a>
      limit,
          non-LRU managed files are limited to 90 percent of this limit,
          which reserves 10 percent of it for LRU managed files.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_optimize_fulltext_only">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_optimize_fulltext_only">
       <code class="literal">
        innodb_optimize_fulltext_only
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153239056">
     </a>
     <a class="indexterm" name="idm46045153237952">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_optimize_fulltext_only">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-optimize-fulltext-only[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_optimize_fulltext_only">
            innodb_optimize_fulltext_only
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Changes the way
      <a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
       <code class="literal">
        OPTIMIZE TABLE
       </code>
      </a>
      operates on
      <code class="literal">
       InnoDB
      </code>
      tables. Intended to be
          enabled temporarily, during maintenance operations for
      <code class="literal">
       InnoDB
      </code>
      tables with
      <code class="literal">
       FULLTEXT
      </code>
      indexes.
     </p>
     <p>
      By default,
      <a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
       <code class="literal">
        OPTIMIZE TABLE
       </code>
      </a>
      reorganizes data in the
      <a class="link" href="glossary.html#glos_clustered_index" title="clustered index">
       clustered index
      </a>
      of
          the table. When this option is enabled,
      <a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
       <code class="literal">
        OPTIMIZE TABLE
       </code>
      </a>
      skips the
          reorganization of table data, and instead processes newly
          added, deleted, and updated token data for
      <code class="literal">
       InnoDB
      </code>
      <code class="literal">
       FULLTEXT
      </code>
      indexes.
          For more information, see
      <a class="xref" href="fulltext-fine-tuning.html#fulltext-optimize" title="Optimizing InnoDB Full-Text Indexes">
       Optimizing InnoDB Full-Text Indexes
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_page_cleaners">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_cleaners">
       <code class="literal">
        innodb_page_cleaners
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153203808">
     </a>
     <a class="indexterm" name="idm46045153202768">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_page_cleaners">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-page-cleaners=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_page_cleaners">
            innodb_page_cleaners
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           innodb_buffer_pool_instances
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of page cleaner threads that flush dirty pages from
          buffer pool instances. Page cleaner threads perform flush list
          and LRU flushing. When there are multiple page cleaner
          threads, buffer pool flushing tasks for each buffer pool
          instance are dispatched to idle page cleaner threads. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_cleaners">
       <code class="literal">
        innodb_page_cleaners
       </code>
      </a>
      default
          value is set to the same value as
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      .
          If the specified number of page cleaner threads exceeds the
          number of buffer pool instances, then
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_cleaners">
       <code class="literal">
        innodb_page_cleaners
       </code>
      </a>
      is
          automatically set to the same value as
      <a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
       <code class="literal">
        innodb_buffer_pool_instances
       </code>
      </a>
      .
     </p>
     <p>
      If your workload is write-IO bound when flushing dirty pages
          from buffer pool instances to data files, and if your system
          hardware has available capacity, increasing the number of page
          cleaner threads may help improve write-IO throughput.
     </p>
     <p>
      Multithreaded page cleaner support extends to shutdown and
          recovery phases.
     </p>
     <p>
      The
      <code class="literal">
       setpriority()
      </code>
      system call is used on
          Linux platforms where it is supported, and where the
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      execution user is authorized to give
      <code class="literal">
       page_cleaner
      </code>
      threads priority over other
          MySQL and
      <code class="literal">
       InnoDB
      </code>
      threads to help page
          flushing keep pace with the current workload.
      <code class="literal">
       setpriority()
      </code>
      support is indicated by this
      <code class="literal">
       InnoDB
      </code>
      startup message:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa59335561"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> If the mysqld execution user is authorized<span class="token punctuation">,</span> page cleaner
thread priority can be changed<span class="token punctuation">.</span> See the man page of setpriority<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span></code></pre>
     </div>
     <p>
      For systems where server startup and shutdown is not managed
          by systemd,
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      execution user
          authorization can be configured in
      <code class="filename">
       /etc/security/limits.conf
      </code>
      . For example,
          if
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      is run under the
      <code class="literal">
       mysql
      </code>
      user, you can authorize the
      <code class="literal">
       mysql
      </code>
      user by adding these lines to
      <code class="filename">
       /etc/security/limits.conf
      </code>
      :
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa42253882"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">mysql              hard    nice       -20
mysql              soft    nice       -20</code></pre>
     </div>
     <p>
      For systemd managed systems, the same can be achieved by
          specifying
      <code class="literal">
       LimitNICE=-20
      </code>
      in a localized
          systemd configuration file. For example, create a file named
      <code class="filename">
       override.conf
      </code>
      in
      <code class="filename">
       /etc/systemd/system/mysqld.service.d/override.conf
      </code>
      and add this entry:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa78683224"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[Service]</span>
<span class="token constant">LimitNICE</span><span class="token attr-value"><span class="token punctuation">=</span>-20</span></code></pre>
     </div>
     <p>
      After creating or changing
      <code class="filename">
       override.conf
      </code>
      ,
          reload the systemd configuration, then tell systemd to restart
          the MySQL service:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa91362659"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">systemctl daemon-reload
systemctl restart mysqld  <span class="token comment" spellcheck="true"># RPM platforms</span>
systemctl restart mysql   <span class="token comment" spellcheck="true"># Debian platforms</span></code></pre>
     </div>
     <p>
      For more information about using a localized systemd
          configuration file, see
      <a class="xref" href="using-systemd.html#systemd-mysql-configuration" title="Configuring systemd for MySQL">
       Configuring systemd for MySQL
      </a>
      .
     </p>
     <p>
      After authorizing the
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      execution
          user, use the
      <span class="command">
       <strong>
        cat
       </strong>
      </span>
      command to verify the
          configured
      <code class="literal">
       Nice
      </code>
      limits for the
      <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
       <span class="command">
        <strong>
         mysqld
        </strong>
       </span>
      </a>
      process:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa80479455"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$&gt; </span><span class="token command">cat</span> /proc/<em class="replaceable">mysqld_pid</em>/limits | grep nice
Max nice priority         18446744073709551596 18446744073709551596</code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_page_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153139920">
     </a>
     <a class="indexterm" name="idm46045153138832">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_page_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-page-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
            innodb_page_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           16384
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            4096
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            8192
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            16384
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            32768
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            65536
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies the
      <a class="link" href="glossary.html#glos_page_size" title="page size">
       page size
      </a>
      for
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_tablespace" title="tablespace">
       tablespaces
      </a>
      . Values can
          be specified in bytes or kilobytes. For example, a 16 kilobyte
          page size value can be specified as 16384, 16KB, or 16k.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      can only be
          configured prior to initializing the MySQL instance and cannot
          be changed afterward. If no value is specified, the instance
          is initialized using the default page size. See
      <a class="xref" href="innodb-init-startup-configuration.html" title="17.8.1 InnoDB Startup Configuration">
       Section 17.8.1, “InnoDB Startup Configuration”
      </a>
      .
     </p>
     <p>
      For both 32KB and 64KB page sizes, the maximum row length is
          approximately 16000 bytes.
      <code class="literal">
       ROW_FORMAT=COMPRESSED
      </code>
      is not supported when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      is set to
          32KB or 64KB. For
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size=32KB
       </code>
      </a>
      , extent
          size is 2MB. For
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size=64KB
       </code>
      </a>
      , extent
          size is 4MB.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_buffer_size">
       <code class="literal">
        innodb_log_buffer_size
       </code>
      </a>
      should
          be set to at least 16MB (the default is 64MB) when using 32KB
          or 64KB page sizes.
     </p>
     <p>
      The default 16KB page size or larger is appropriate for a wide
          range of
      <a class="link" href="glossary.html#glos_workload" title="workload">
       workloads
      </a>
      ,
          particularly for queries involving table scans and DML
          operations involving bulk updates. Smaller page sizes might be
          more efficient for
      <a class="link" href="glossary.html#glos_oltp" title="OLTP">
       OLTP
      </a>
      workloads involving many small writes, where contention can be
          an issue when single pages contain many rows. Smaller pages
          might also be efficient with
      <a class="link" href="glossary.html#glos_ssd" title="SSD">
       SSD
      </a>
      storage devices, which
          typically use small block sizes. Keeping the
      <code class="literal">
       InnoDB
      </code>
      page size close to the storage
          device block size minimizes the amount of unchanged data that
          is rewritten to disk.
     </p>
     <p>
      The minimum file size for the first system tablespace data
          file (
      <code class="literal">
       ibdata1
      </code>
      ) differs depending on the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_page_size">
       <code class="literal">
        innodb_page_size
       </code>
      </a>
      value. See
          the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_file_path">
       <code class="literal">
        innodb_data_file_path
       </code>
      </a>
      option description for more information.
     </p>
     <p>
      A MySQL instance using a particular
      <code class="literal">
       InnoDB
      </code>
      page size cannot use data files or log files from an instance
          that uses a different page size.
     </p>
     <p>
      For general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_parallel_read_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_parallel_read_threads">
       <code class="literal">
        innodb_parallel_read_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153085744">
     </a>
     <a class="indexterm" name="idm46045153084640">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_parallel_read_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-parallel-read-threads=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_parallel_read_threads">
            innodb_parallel_read_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           (available logical processors / 8), min of 4
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           256
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the number of threads that can be used for parallel
          clustered index reads. Parallel scanning of partitions is also
          supported. Parallel read threads can improve
      <a class="link" href="check-table.html" title="15.7.3.2 CHECK TABLE Statement">
       <code class="literal">
        CHECK TABLE
       </code>
      </a>
      performance.
      <code class="literal">
       InnoDB
      </code>
      reads the clustered index twice
          during a
      <a class="link" href="check-table.html" title="15.7.3.2 CHECK TABLE Statement">
       <code class="literal">
        CHECK TABLE
       </code>
      </a>
      operation.
          The second read can be performed in parallel. This feature
          does not apply to secondary index scans. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_parallel_read_threads">
       <code class="literal">
        innodb_parallel_read_threads
       </code>
      </a>
      session variable must be set to a value greater than 1 for
          parallel clustered index reads to occur. The actual number of
          threads used to perform a parallel clustered index read is
          determined by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_parallel_read_threads">
       <code class="literal">
        innodb_parallel_read_threads
       </code>
      </a>
      setting or the number of index subtrees to scan, whichever is
          smaller. The pages read into the buffer pool during the scan
          are kept at the tail of the buffer pool LRU list so that they
          can be discarded quickly when free buffer pool pages are
          required.
     </p>
     <p>
      The maximum number of parallel read threads (256) is the total
          number of threads for all client connections. If the thread
          limit is reached, connections fall back to using a single
          thread. The default value is calculated by the number of
          available logical processors on the system divided by 8, with
          a minimum default value of 4.
     </p>
     <p>
      Before MySQL 8.4, the default value was always 4.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_print_all_deadlocks">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_print_all_deadlocks">
       <code class="literal">
        innodb_print_all_deadlocks
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153047264">
     </a>
     <a class="indexterm" name="idm46045153046160">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_print_all_deadlocks">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-print-all-deadlocks[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_print_all_deadlocks">
            innodb_print_all_deadlocks
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <a class="indexterm" name="idm46045153024448">
     </a>
     <p>
      When this option is enabled, information about all
      <a class="link" href="glossary.html#glos_deadlock" title="deadlock">
       deadlocks
      </a>
      in
      <code class="literal">
       InnoDB
      </code>
      user transactions is recorded in the
      <code class="literal">
       mysqld
      </code>
      <a class="link" href="error-log.html" title="7.4.2 The Error Log">
       error
          log
      </a>
      . Otherwise, you see information about only the last
          deadlock, using the
      <code class="literal">
       SHOW ENGINE INNODB
          STATUS
      </code>
      statement. An occasional
      <code class="literal">
       InnoDB
      </code>
      deadlock is not necessarily an
          issue, because
      <code class="literal">
       InnoDB
      </code>
      detects the condition
          immediately and rolls back one of the transactions
          automatically. You might use this option to troubleshoot why
          deadlocks are occurring if an application does not have
          appropriate error-handling logic to detect the rollback and
          retry its operation. A large number of deadlocks might
          indicate the need to restructure transactions that issue
      <a class="link" href="glossary.html#glos_dml" title="DML">
       DML
      </a>
      or
      <code class="literal">
       SELECT ... FOR
          UPDATE
      </code>
      statements for multiple tables, so that each
          transaction accesses the tables in the same order, thus
          avoiding the deadlock condition.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-deadlocks.html" title="17.7.5 Deadlocks in InnoDB">
       Section 17.7.5, “Deadlocks in InnoDB”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_print_ddl_logs">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_print_ddl_logs">
       <code class="literal">
        innodb_print_ddl_logs
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045153011760">
     </a>
     <a class="indexterm" name="idm46045153010720">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_print_ddl_logs">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-print-ddl-logs[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_print_ddl_logs">
            innodb_print_ddl_logs
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enabling this option causes MySQL to write DDL logs to
      <code class="literal">
       stderr
      </code>
      . For more information, see
      <a class="xref" href="atomic-ddl.html#atomic-ddl-view-logs" title="Viewing DDL Logs">
       Viewing DDL Logs
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_purge_batch_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
       <code class="literal">
        innodb_purge_batch_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152984688">
     </a>
     <a class="indexterm" name="idm46045152983648">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_purge_batch_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-purge-batch-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
            innodb_purge_batch_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           300
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           5000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the number of undo log pages that purge parses and
          processes in one batch from the
      <a class="link" href="glossary.html#glos_history_list" title="history list">
       history list
      </a>
      . In a
          multithreaded purge configuration, the coordinator purge
          thread divides
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
       <code class="literal">
        innodb_purge_batch_size
       </code>
      </a>
      by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_threads">
       <code class="literal">
        innodb_purge_threads
       </code>
      </a>
      and
          assigns that number of pages to each purge thread. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
       <code class="literal">
        innodb_purge_batch_size
       </code>
      </a>
      variable also defines the number of undo log pages that purge
          frees after every 128 iterations through the undo logs.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
       <code class="literal">
        innodb_purge_batch_size
       </code>
      </a>
      option is intended for advanced performance tuning in
          combination with the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_threads">
       <code class="literal">
        innodb_purge_threads
       </code>
      </a>
      setting.
          Most users need not change
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_batch_size">
       <code class="literal">
        innodb_purge_batch_size
       </code>
      </a>
      from
          its default value.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-purge-configuration.html" title="17.8.9 Purge Configuration">
       Section 17.8.9, “Purge Configuration”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_purge_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_threads">
       <code class="literal">
        innodb_purge_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152943488">
     </a>
     <a class="indexterm" name="idm46045152942448">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_purge_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-purge-threads=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_threads">
            innodb_purge_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1 if # of available logical processors is &lt;= 16; otherwise 4
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           32
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of background threads devoted to the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_purge" title="purge">
       purge
      </a>
      operation. Increasing
          the value creates additional purge threads, which can improve
          efficiency on systems where
      <a class="link" href="glossary.html#glos_dml" title="DML">
       DML
      </a>
      operations are performed
          on multiple tables.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-purge-configuration.html" title="17.8.9 Purge Configuration">
       Section 17.8.9, “Purge Configuration”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_purge_rseg_truncate_frequency">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_rseg_truncate_frequency">
       <code class="literal">
        innodb_purge_rseg_truncate_frequency
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152909168">
     </a>
     <a class="indexterm" name="idm46045152908128">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_purge_rseg_truncate_frequency">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-purge-rseg-truncate-frequency=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_rseg_truncate_frequency">
            innodb_purge_rseg_truncate_frequency
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           128
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           128
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the frequency with which the purge system frees
          rollback segments in terms of the number of times that purge
          is invoked. An undo tablespace cannot be truncated until its
          rollback segments are freed. Normally, the purge system frees
          rollback segments once every 128 times that purge is invoked.
          The default value is 128. Reducing this value increases the
          frequency with which the purge thread frees rollback segments.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_rseg_truncate_frequency">
       <code class="literal">
        innodb_purge_rseg_truncate_frequency
       </code>
      </a>
      is intended for use with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_truncate">
       <code class="literal">
        innodb_undo_log_truncate
       </code>
      </a>
      . For
          more information, see
      <a class="xref" href="innodb-undo-tablespaces.html#truncate-undo-tablespace" title="Truncating Undo Tablespaces">
       Truncating Undo Tablespaces
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_random_read_ahead">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_random_read_ahead">
       <code class="literal">
        innodb_random_read_ahead
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152874432">
     </a>
     <a class="indexterm" name="idm46045152873328">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_random_read_ahead">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-random-read-ahead[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_random_read_ahead">
            innodb_random_read_ahead
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables the random
      <a class="link" href="glossary.html#glos_read_ahead" title="read-ahead">
       read-ahead
      </a>
      technique
          for optimizing
      <code class="literal">
       InnoDB
      </code>
      I/O.
     </p>
     <p>
      For details about performance considerations for different
          types of read-ahead requests, see
      <a class="xref" href="innodb-performance-read_ahead.html" title="17.8.3.4 Configuring InnoDB Buffer Pool Prefetching (Read-Ahead)">
       Section 17.8.3.4, “Configuring InnoDB Buffer Pool Prefetching (Read-Ahead)”
      </a>
      . For general
          I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_read_ahead_threshold">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_ahead_threshold">
       <code class="literal">
        innodb_read_ahead_threshold
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045309042080">
     </a>
     <a class="indexterm" name="idm46045309041040">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_read_ahead_threshold">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-read-ahead-threshold=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_read_ahead_threshold">
            innodb_read_ahead_threshold
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           56
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls the sensitivity of linear
      <a class="link" href="glossary.html#glos_read_ahead" title="read-ahead">
       read-ahead
      </a>
      that
      <code class="literal">
       InnoDB
      </code>
      uses to prefetch pages into the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer pool
      </a>
      . If
      <code class="literal">
       InnoDB
      </code>
      reads at least
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_ahead_threshold">
       <code class="literal">
        innodb_read_ahead_threshold
       </code>
      </a>
      pages sequentially from an
      <a class="link" href="glossary.html#glos_extent" title="extent">
       extent
      </a>
      (64 pages), it
          initiates an asynchronous read for the entire following
          extent. The permissible range of values is 0 to 64. A value of
          0 disables read-ahead. For the default of 56,
      <code class="literal">
       InnoDB
      </code>
      must read at least 56 pages
          sequentially from an extent to initiate an asynchronous read
          for the following extent.
     </p>
     <p>
      Knowing how many pages are read through the read-ahead
          mechanism, and how many of these pages are evicted from the
          buffer pool without ever being accessed, can be useful when
          fine-tuning the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_ahead_threshold">
       <code class="literal">
        innodb_read_ahead_threshold
       </code>
      </a>
      setting.
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW
          ENGINE INNODB STATUS
       </code>
      </a>
      output displays counter
          information from the
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_ahead">
       <code class="literal">
        Innodb_buffer_pool_read_ahead
       </code>
      </a>
      and
      <a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_read_ahead_evicted">
       <code class="literal">
        Innodb_buffer_pool_read_ahead_evicted
       </code>
      </a>
      global status variables, which report the number of pages
          brought into the
      <a class="link" href="glossary.html#glos_buffer_pool" title="buffer pool">
       buffer
          pool
      </a>
      by read-ahead requests, and the number of such
          pages
      <a class="link" href="glossary.html#glos_eviction" title="eviction">
       evicted
      </a>
      from the
          buffer pool without ever being accessed, respectively. The
          status variables report global values since the last server
          restart.
     </p>
     <p>
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB STATUS
       </code>
      </a>
      also shows the rate at which the
          read-ahead pages are read and the rate at which such pages are
          evicted without being accessed. The per-second averages are
          based on the statistics collected since the last invocation of
      <code class="literal">
       SHOW ENGINE INNODB STATUS
      </code>
      and are displayed
          in the
      <code class="literal">
       BUFFER POOL AND MEMORY
      </code>
      section of
          the
      <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
       <code class="literal">
        SHOW ENGINE
          INNODB STATUS
       </code>
      </a>
      output.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-read_ahead.html" title="17.8.3.4 Configuring InnoDB Buffer Pool Prefetching (Read-Ahead)">
       Section 17.8.3.4, “Configuring InnoDB Buffer Pool Prefetching (Read-Ahead)”
      </a>
      . For general
          I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_read_io_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
       <code class="literal">
        innodb_read_io_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045308991376">
     </a>
     <a class="indexterm" name="idm46045308990336">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_read_io_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-read-io-threads=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
            innodb_read_io_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           (available logical processors / 2), min of 4
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of I/O threads for read operations in
      <code class="literal">
       InnoDB
      </code>
      . Its counterpart for write threads
          is
      <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
       <code class="literal">
        innodb_write_io_threads
       </code>
      </a>
      .
          For more information, see
      <a class="xref" href="innodb-performance-multiple_io_threads.html" title="17.8.5 Configuring the Number of Background InnoDB I/O Threads">
       Section 17.8.5, “Configuring the Number of Background InnoDB I/O Threads”
      </a>
      . For
          general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      . The default value
          is the number of available logical processors on the system
          divided by 2, with a minimum default value of 4.
     </p>
     <p>
      Before MySQL 8.4, the default value was always 4.
     </p>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       On Linux systems, running multiple MySQL servers (typically
            more than 12) with default settings for
       <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
        <code class="literal">
         innodb_read_io_threads
        </code>
       </a>
       ,
       <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
        <code class="literal">
         innodb_write_io_threads
        </code>
       </a>
       ,
            and the Linux
       <code class="literal">
        aio-max-nr
       </code>
       setting can
            exceed system limits. Ideally, increase the
       <code class="literal">
        aio-max-nr
       </code>
       setting; as a workaround, you
            might reduce the settings for one or both of the MySQL
            variables.
      </p>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_read_only">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
       <code class="literal">
        innodb_read_only
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045308952064">
     </a>
     <a class="indexterm" name="idm46045308950976">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_read_only">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-read-only[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
            innodb_read_only
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Starts
      <code class="literal">
       InnoDB
      </code>
      in read-only mode. For
          distributing database applications or data sets on read-only
          media. Can also be used in data warehouses to share the same
          data directory between multiple instances. For more
          information, see
      <a class="xref" href="innodb-read-only-instance.html" title="17.8.2 Configuring InnoDB for Read-Only Operation">
       Section 17.8.2, “Configuring InnoDB for Read-Only Operation”
      </a>
      .
     </p>
     <p>
      Enabling
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
       <code class="literal">
        innodb_read_only
       </code>
      </a>
      prevents creating and dropping tables for all storage engines,
          and not only
      <code class="literal">
       InnoDB
      </code>
      . Table creation and
          drop operations for any storage engine modify data dictionary
          tables in the
      <code class="literal">
       mysql
      </code>
      system database, but
          those tables use the
      <code class="literal">
       InnoDB
      </code>
      storage engine
          and cannot be modified when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
       <code class="literal">
        innodb_read_only
       </code>
      </a>
      is enabled.
          The same principle applies to other table operations that
          require modifying data dictionary tables. Examples:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         If the
         <a class="link" href="innodb-parameters.html#sysvar_innodb_read_only">
          <code class="literal">
           innodb_read_only
          </code>
         </a>
         system variable is enabled,
         <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
          <code class="literal">
           ANALYZE
              TABLE
          </code>
         </a>
         may fail because it cannot update
              statistics tables in the data dictionary, which use
         <code class="literal">
          InnoDB
         </code>
         . For
         <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
          <code class="literal">
           ANALYZE TABLE
          </code>
         </a>
         operations
              that update the key distribution, failure may occur even
              if the operation updates the table itself (for example, if
              it is a
         <code class="literal">
          MyISAM
         </code>
         table). To obtain the
              updated distribution statistics, set
         <a class="link" href="server-system-variables.html#sysvar_information_schema_stats_expiry">
          <code class="literal">
           information_schema_stats_expiry=0
          </code>
         </a>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
          <code class="literal">
           ALTER TABLE
           <em class="replaceable">
            <code>
             tbl_name
            </code>
           </em>
           ENGINE=
           <em class="replaceable">
            <code>
             engine_name
            </code>
           </em>
          </code>
         </a>
         fails because it updates the storage engine designation,
              which is stored in the data dictionary.
        </p>
       </li>
      </ul>
     </div>
     <p>
      In addition, other tables in the
      <code class="literal">
       mysql
      </code>
      system database use the
      <code class="literal">
       InnoDB
      </code>
      storage
          engine. Making those tables read-only results in restrictions
          on operations that modify them. Examples:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         Account-management statements such as
         <a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
          <code class="literal">
           CREATE USER
          </code>
         </a>
         and
         <a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
          <code class="literal">
           GRANT
          </code>
         </a>
         fail because the
              grant tables use
         <code class="literal">
          InnoDB
         </code>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         The
         <a class="link" href="install-plugin.html" title="15.7.4.4 INSTALL PLUGIN Statement">
          <code class="literal">
           INSTALL PLUGIN
          </code>
         </a>
         and
         <a class="link" href="uninstall-plugin.html" title="15.7.4.6 UNINSTALL PLUGIN Statement">
          <code class="literal">
           UNINSTALL PLUGIN
          </code>
         </a>
         plugin-management statements fail because the
         <code class="literal">
          mysql.plugin
         </code>
         system table uses
         <code class="literal">
          InnoDB
         </code>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         The
         <a class="link" href="create-function-loadable.html" title="15.7.4.1 CREATE FUNCTION Statement for Loadable Functions">
          <code class="literal">
           CREATE
              FUNCTION
          </code>
         </a>
         and
         <a class="link" href="drop-function-loadable.html" title="15.7.4.2 DROP FUNCTION Statement for Loadable Functions">
          <code class="literal">
           DROP
              FUNCTION
          </code>
         </a>
         loadable function-management statements
              fail because the
         <code class="literal">
          mysql.func
         </code>
         system
              table uses
         <code class="literal">
          InnoDB
         </code>
         .
        </p>
       </li>
      </ul>
     </div>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_redo_log_archive_dirs">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_archive_dirs">
       <code class="literal">
        innodb_redo_log_archive_dirs
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152799920">
     </a>
     <a class="indexterm" name="idm46045152798912">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_redo_log_archive_dirs">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-redo-log-archive-dirs
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_archive_dirs">
            innodb_redo_log_archive_dirs
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines labeled directories where redo log archive files can
          be created. You can define multiple labeled directories in a
          semicolon-separated list. For example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa2846136"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">innodb_redo_log_archive_dirs</span><span class="token attr-value"><span class="token punctuation">=</span>'label1:/backups1;label2:/backups2'</span></code></pre>
     </div>
     <p>
      A label can be any string of characters, with the exception of
          colons (:), which are not permitted. An empty label is also
          permitted, but the colon (:) is still required in this case.
     </p>
     <p>
      A path must be specified, and the directory must exist. The
          path can contain colons (':'), but semicolons (;) are not
          permitted.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_redo_log_capacity">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
       <code class="literal">
        innodb_redo_log_capacity
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152773584">
     </a>
     <a class="indexterm" name="idm46045152772576">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_redo_log_capacity">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-redo-log-capacity=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
            innodb_redo_log_capacity
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           104857600
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           8388608
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           549755813888
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the amount of disk space occupied by redo log files.
     </p>
     <p>
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      supercedes the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_files_in_group">
       <code class="literal">
        innodb_log_files_in_group
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_log_file_size">
       <code class="literal">
        innodb_log_file_size
       </code>
      </a>
      variables, which are both ignored if
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      is defined.
     </p>
     <p>
      If
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      is not defined,
          and if neither
      <code class="literal">
       innodb_log_file_size
      </code>
      or
      <code class="literal">
       innodb_log_files_in_group
      </code>
      are defined, then
          the default
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      value
          is used.
     </p>
     <p>
      If
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      is not defined,
          and if
      <code class="literal">
       innodb_log_file_size
      </code>
      and/or
      <code class="literal">
       innodb_log_files_in_group
      </code>
      is defined, then
          the InnoDB redo log capacity is calculated as
      <span class="emphasis">
       <em>
        (innodb_log_files_in_group *
          innodb_log_file_size)
       </em>
      </span>
      . This calculation does not
          modify the unused
      <code class="literal">
       innodb_redo_log_capacity
      </code>
      setting's value.
     </p>
     <p>
      The
      <a class="link" href="server-status-variables.html#statvar_Innodb_redo_log_capacity_resized">
       <code class="literal">
        Innodb_redo_log_capacity_resized
       </code>
      </a>
      server status variable indicates the total redo log capacity
          for all redo log files.
     </p>
     <p>
      If the server is started with
      <a class="link" href="innodb-parameters.html#option_mysqld_innodb-dedicated-server">
       <code class="option">
        --innodb-dedicated-server
       </code>
      </a>
      , the
          value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_capacity">
       <code class="literal">
        innodb_redo_log_capacity
       </code>
      </a>
      is
          set automatically if it is not explicitly defined. For more
          information, see
      <a class="xref" href="innodb-dedicated-server.html" title="17.8.12 Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server">
       Section 17.8.12, “Enabling Automatic InnoDB Configuration for a Dedicated MySQL Server”
      </a>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-redo-log.html" title="17.6.5 Redo Log">
       Section 17.6.5, “Redo Log”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_redo_log_encrypt">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_encrypt">
       <code class="literal">
        innodb_redo_log_encrypt
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152727616">
     </a>
     <a class="indexterm" name="idm46045152726608">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_redo_log_encrypt">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-redo-log-encrypt[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_redo_log_encrypt">
            innodb_redo_log_encrypt
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls encryption of redo log data for tables encrypted
          using the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="innodb-data-encryption.html" title="17.13 InnoDB Data-at-Rest Encryption">
       data-at-rest encryption
          feature
      </a>
      . Encryption of redo log data is disabled by
          default. For more information, see
      <a class="xref" href="innodb-data-encryption.html#innodb-data-encryption-redo-log" title="Redo Log Encryption">
       Redo Log Encryption
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_replication_delay">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_replication_delay">
       <code class="literal">
        innodb_replication_delay
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152701680">
     </a>
     <a class="indexterm" name="idm46045152700672">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_replication_delay">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-replication-delay=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_replication_delay">
            innodb_replication_delay
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          milliseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The replication thread delay in milliseconds on a replica
          server if
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      is
          reached.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_rollback_on_timeout">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_on_timeout">
       <code class="literal">
        innodb_rollback_on_timeout
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152669920">
     </a>
     <a class="indexterm" name="idm46045152668912">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_rollback_on_timeout">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-rollback-on-timeout[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_on_timeout">
            innodb_rollback_on_timeout
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="glossary.html#glos_rollback" title="rollback">
       rolls
          back
      </a>
      only the last statement on a transaction timeout
          by default. If
      <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_on_timeout">
       <code class="option">
        --innodb-rollback-on-timeout
       </code>
      </a>
      is
          specified, a transaction timeout causes
      <code class="literal">
       InnoDB
      </code>
      to abort and roll back the entire
          transaction.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-error-handling.html" title="17.20.5 InnoDB Error Handling">
       Section 17.20.5, “InnoDB Error Handling”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_rollback_segments">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_segments">
       <code class="literal">
        innodb_rollback_segments
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152642192">
     </a>
     <a class="indexterm" name="idm46045152641184">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_rollback_segments">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-rollback-segments=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_segments">
            innodb_rollback_segments
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           128
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           128
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_rollback_segments">
       <code class="literal">
        innodb_rollback_segments
       </code>
      </a>
      defines the number of
      <a class="link" href="glossary.html#glos_rollback_segment" title="rollback segment">
       rollback segments
      </a>
      allocated to each undo tablespace and the global temporary
          tablespace for transactions that generate undo records. The
          number of transactions that each rollback segment supports
          depends on the
      <code class="literal">
       InnoDB
      </code>
      page size and the
          number of undo logs assigned to each transaction. For more
          information, see
      <a class="xref" href="innodb-undo-logs.html" title="17.6.6 Undo Logs">
       Section 17.6.6, “Undo Logs”
      </a>
      .
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-multi-versioning.html" title="17.3 InnoDB Multi-Versioning">
       Section 17.3, “InnoDB Multi-Versioning”
      </a>
      . For information
          about undo tablespaces, see
      <a class="xref" href="innodb-undo-tablespaces.html" title="17.6.3.4 Undo Tablespaces">
       Section 17.6.3.4, “Undo Tablespaces”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_saved_page_number_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
       <code class="literal">
        innodb_saved_page_number_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152608944">
     </a>
     <a class="indexterm" name="idm46045152607936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_saved_page_number_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-saved-page-number-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
            innodb_saved_page_number_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           2**32-1
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Saves a page number. Setting the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_fil_make_page_dirty_debug">
       <code class="literal">
        innodb_fil_make_page_dirty_debug
       </code>
      </a>
      option dirties the page defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
       <code class="literal">
        innodb_saved_page_number_debug
       </code>
      </a>
      .
          The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_saved_page_number_debug">
       <code class="literal">
        innodb_saved_page_number_debug
       </code>
      </a>
      option is only available if debugging support is compiled in
          using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_segment_reserve_factor">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_segment_reserve_factor">
       <code class="literal">
        innodb_segment_reserve_factor
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152575728">
     </a>
     <a class="indexterm" name="idm46045152574720">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_segment_reserve_factor">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-segment-reserve-factor=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_segment_reserve_factor">
            innodb_segment_reserve_factor
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Numeric
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           12.5
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0.03
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           40
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the percentage of tablespace file segment pages
          reserved as empty pages. The setting is applicable to
          file-per-table and general tablespaces. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_segment_reserve_factor">
       <code class="literal">
        innodb_segment_reserve_factor
       </code>
      </a>
      default setting is 12.5 percent, which is the same percentage
          of pages reserved in previous MySQL releases.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-file-space.html#innodb-config-reserved-file-segment-pages" title="Configuring the Percentage of Reserved File Segment Pages">
       Configuring the Percentage of Reserved File Segment Pages
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_sort_buffer_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sort_buffer_size">
       <code class="literal">
        innodb_sort_buffer_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152544816">
     </a>
     <a class="indexterm" name="idm46045152543808">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_sort_buffer_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-sort-buffer-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_sort_buffer_size">
            innodb_sort_buffer_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1048576
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           65536
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           67108864
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          bytes
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This variable defines the amount by which the temporary log
          file is extended when recording concurrent DML during an
      <a class="link" href="glossary.html#glos_online_ddl" title="online DDL">
       online DDL
      </a>
      operation,
          and the size of the temporary log file read buffer and write
          buffer.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-online-ddl-space-requirements.html" title="17.12.3 Online DDL Space Requirements">
       Section 17.12.3, “Online DDL Space Requirements”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_spin_wait_delay">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_delay">
       <code class="literal">
        innodb_spin_wait_delay
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152512368">
     </a>
     <a class="indexterm" name="idm46045152511360">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_spin_wait_delay">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-spin-wait-delay=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_delay">
            innodb_spin_wait_delay
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           6
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The maximum delay between polls for a
      <a class="link" href="glossary.html#glos_spin" title="spin">
       spin
      </a>
      lock. The low-level
          implementation of this mechanism varies depending on the
          combination of hardware and operating system, so the delay
          does not correspond to a fixed time interval.
     </p>
     <p>
      Can be used in combination with the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_pause_multiplier">
       <code class="literal">
        innodb_spin_wait_pause_multiplier
       </code>
      </a>
      variable for greater control over the duration of spin-lock
          polling delays.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-spin_lock_polling.html" title="17.8.8 Configuring Spin Lock Polling">
       Section 17.8.8, “Configuring Spin Lock Polling”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_spin_wait_pause_multiplier">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_pause_multiplier">
       <code class="literal">
        innodb_spin_wait_pause_multiplier
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152480288">
     </a>
     <a class="indexterm" name="idm46045152479280">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_spin_wait_pause_multiplier">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-spin-wait-pause-multiplier=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_spin_wait_pause_multiplier">
            innodb_spin_wait_pause_multiplier
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           50
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           100
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines a multiplier value used to determine the number of
          PAUSE instructions in spin-wait loops that occur when a thread
          waits to acquire a mutex or rw-lock.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-spin_lock_polling.html" title="17.8.8 Configuring Spin Lock Polling">
       Section 17.8.8, “Configuring Spin Lock Polling”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_auto_recalc">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_auto_recalc">
       <code class="literal">
        innodb_stats_auto_recalc
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152450528">
     </a>
     <a class="indexterm" name="idm46045152449520">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_auto_recalc">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-auto-recalc[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_auto_recalc">
            innodb_stats_auto_recalc
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Causes
      <code class="literal">
       InnoDB
      </code>
      to automatically recalculate
      <a class="link" href="glossary.html#glos_persistent_statistics" title="persistent statistics">
       persistent
          statistics
      </a>
      after the data in a table is changed
          substantially. The threshold value is 10% of the rows in the
          table. This setting applies to tables created when the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      option is enabled. Automatic statistics recalculation may also
          be configured by specifying
      <code class="literal">
       STATS_AUTO_RECALC=1
      </code>
      in a
      <a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
       <code class="literal">
        CREATE TABLE
       </code>
      </a>
      or
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      statement. The
          amount of data sampled to produce the statistics is controlled
          by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
       <code class="literal">
        innodb_stats_persistent_sample_pages
       </code>
      </a>
      variable.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-persistent-stats.html" title="17.8.10.1 Configuring Persistent Optimizer Statistics Parameters">
       Section 17.8.10.1, “Configuring Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_include_delete_marked">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
       <code class="literal">
        innodb_stats_include_delete_marked
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152419360">
     </a>
     <a class="indexterm" name="idm46045152418352">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_include_delete_marked">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-include-delete-marked[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
            innodb_stats_include_delete_marked
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      By default,
      <code class="literal">
       InnoDB
      </code>
      reads uncommitted data
          when calculating statistics. In the case of an uncommitted
          transaction that deletes rows from a table,
      <code class="literal">
       InnoDB
      </code>
      excludes records that are
          delete-marked when calculating row estimates and index
          statistics, which can lead to non-optimal execution plans for
          other transactions that are operating on the table
          concurrently using a transaction isolation level other than
      <a class="link" href="innodb-transaction-isolation-levels.html#isolevel_read-uncommitted">
       <code class="literal">
        READ UNCOMMITTED
       </code>
      </a>
      . To avoid
          this scenario,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
       <code class="literal">
        innodb_stats_include_delete_marked
       </code>
      </a>
      can be enabled to ensure that
      <code class="literal">
       InnoDB
      </code>
      includes delete-marked records when calculating persistent
          optimizer statistics.
     </p>
     <p>
      When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
       <code class="literal">
        innodb_stats_include_delete_marked
       </code>
      </a>
      is enabled,
      <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
       <code class="literal">
        ANALYZE TABLE
       </code>
      </a>
      considers delete-marked records when recalculating statistics.
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_include_delete_marked">
       <code class="literal">
        innodb_stats_include_delete_marked
       </code>
      </a>
      is a global setting that affects all
      <code class="literal">
       InnoDB
      </code>
      tables. It is only applicable to persistent optimizer
          statistics.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-persistent-stats.html" title="17.8.10.1 Configuring Persistent Optimizer Statistics Parameters">
       Section 17.8.10.1, “Configuring Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_method">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_method">
       <code class="literal">
        innodb_stats_method
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152385456">
     </a>
     <a class="indexterm" name="idm46045152384448">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_method">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-method=value
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_method">
            innodb_stats_method
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Enumeration
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           nulls_equal
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Valid Values
         </th>
         <td>
          <p class="valid-value">
           <code class="literal">
            nulls_equal
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            nulls_unequal
           </code>
          </p>
          <p class="valid-value">
           <code class="literal">
            nulls_ignored
           </code>
          </p>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      How the server treats
      <code class="literal">
       NULL
      </code>
      values when
          collecting
      <a class="link" href="glossary.html#glos_statistics" title="statistics">
       statistics
      </a>
      about the distribution of index values for
      <code class="literal">
       InnoDB
      </code>
      tables. Permitted values are
      <code class="literal">
       nulls_equal
      </code>
      ,
      <code class="literal">
       nulls_unequal
      </code>
      , and
      <code class="literal">
       nulls_ignored
      </code>
      . For
      <code class="literal">
       nulls_equal
      </code>
      , all
      <code class="literal">
       NULL
      </code>
      index values are considered equal and form a single value
          group with a size equal to the number of
      <code class="literal">
       NULL
      </code>
      values. For
      <code class="literal">
       nulls_unequal
      </code>
      ,
      <code class="literal">
       NULL
      </code>
      values are considered unequal, and each
      <code class="literal">
       NULL
      </code>
      forms a distinct value group of size
          1. For
      <code class="literal">
       nulls_ignored
      </code>
      ,
      <code class="literal">
       NULL
      </code>
      values are ignored.
     </p>
     <p>
      The method used to generate table statistics influences how
          the optimizer chooses indexes for query execution, as
          described in
      <a class="xref" href="index-statistics.html" title="10.3.8 InnoDB and MyISAM Index Statistics Collection">
       Section 10.3.8, “InnoDB and MyISAM Index Statistics Collection”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_on_metadata">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_on_metadata">
       <code class="literal">
        innodb_stats_on_metadata
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152346944">
     </a>
     <a class="indexterm" name="idm46045152345936">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_on_metadata">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-on-metadata[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_on_metadata">
            innodb_stats_on_metadata
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      This option only applies when optimizer
      <a class="link" href="glossary.html#glos_statistics" title="statistics">
       statistics
      </a>
      are
          configured to be non-persistent. Optimizer statistics are not
          persisted to disk when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      is
          disabled or when individual tables are created or altered with
      <code class="literal">
       STATS_PERSISTENT=0
      </code>
      . For more information,
          see
      <a class="xref" href="innodb-statistics-estimation.html" title="17.8.10.2 Configuring Non-Persistent Optimizer Statistics Parameters">
       Section 17.8.10.2, “Configuring Non-Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
     <p>
      When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_on_metadata">
       <code class="literal">
        innodb_stats_on_metadata
       </code>
      </a>
      is enabled,
      <code class="literal">
       InnoDB
      </code>
      updates non-persistent
      <a class="link" href="glossary.html#glos_statistics" title="statistics">
       statistics
      </a>
      when
          metadata statements such as
      <a class="link" href="show-table-status.html" title="15.7.7.38 SHOW TABLE STATUS Statement">
       <code class="literal">
        SHOW TABLE
          STATUS
       </code>
      </a>
      or when accessing the Information Schema
      <a class="link" href="information-schema-tables-table.html" title="28.3.38 The INFORMATION_SCHEMA TABLES Table">
       <code class="literal">
        TABLES
       </code>
      </a>
      or
      <a class="link" href="information-schema-statistics-table.html" title="28.3.34 The INFORMATION_SCHEMA STATISTICS Table">
       <code class="literal">
        STATISTICS
       </code>
      </a>
      tables. (These updates
          are similar to what happens for
      <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
       <code class="literal">
        ANALYZE
          TABLE
       </code>
      </a>
      .) When disabled,
      <code class="literal">
       InnoDB
      </code>
      does not update statistics during these operations. Leaving
          the setting disabled can improve access speed for schemas that
          have a large number of tables or indexes. It can also improve
          the stability of
      <a class="link" href="glossary.html#glos_query_execution_plan" title="query execution plan">
       execution
          plans
      </a>
      for queries that involve
      <code class="literal">
       InnoDB
      </code>
      tables.
     </p>
     <p>
      To change the setting, issue the statement
      <code class="literal">
       SET GLOBAL
          innodb_stats_on_metadata=
       <em class="replaceable">
        <code>
         mode
        </code>
       </em>
      </code>
      ,
          where
      <code class="literal">
       <em class="replaceable">
        <code>
         mode
        </code>
       </em>
      </code>
      is
          either
      <code class="literal">
       ON
      </code>
      or
      <code class="literal">
       OFF
      </code>
      (or
      <code class="literal">
       1
      </code>
      or
      <code class="literal">
       0
      </code>
      ). Changing the
          setting requires privileges sufficient to set global system
          variables (see
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      )
          and immediately affects the operation of all connections.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_persistent">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152305872">
     </a>
     <a class="indexterm" name="idm46045152304864">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_persistent">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-persistent[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
            innodb_stats_persistent
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies whether
      <code class="literal">
       InnoDB
      </code>
      index statistics
          are persisted to disk. Otherwise, statistics may be
          recalculated frequently which can lead to variations in
      <a class="link" href="glossary.html#glos_query_execution_plan" title="query execution plan">
       query execution
          plans
      </a>
      . This setting is stored with each table when the
          table is created. You can set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      at
          the global level before creating a table, or use the
      <code class="literal">
       STATS_PERSISTENT
      </code>
      clause of the
      <a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
       <code class="literal">
        CREATE TABLE
       </code>
      </a>
      and
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      statements to
          override the system-wide setting and configure persistent
          statistics for individual tables.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-persistent-stats.html" title="17.8.10.1 Configuring Persistent Optimizer Statistics Parameters">
       Section 17.8.10.1, “Configuring Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_persistent_sample_pages">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
       <code class="literal">
        innodb_stats_persistent_sample_pages
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152275648">
     </a>
     <a class="indexterm" name="idm46045152274640">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_persistent_sample_pages">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-persistent-sample-pages=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
            innodb_stats_persistent_sample_pages
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           20
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           18446744073709551615
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of index
      <a class="link" href="glossary.html#glos_page" title="page">
       pages
      </a>
      to
          sample when estimating
      <a class="link" href="glossary.html#glos_cardinality" title="cardinality">
       cardinality
      </a>
      and other
      <a class="link" href="glossary.html#glos_statistics" title="statistics">
       statistics
      </a>
      for an
          indexed column, such as those calculated by
      <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
       <code class="literal">
        ANALYZE TABLE
       </code>
      </a>
      . Increasing the
          value improves the accuracy of index statistics, which can
          improve the
      <a class="link" href="glossary.html#glos_query_execution_plan" title="query execution plan">
       query
          execution plan
      </a>
      , at the expense of increased I/O during
          the execution of
      <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
       <code class="literal">
        ANALYZE TABLE
       </code>
      </a>
      for an
      <code class="literal">
       InnoDB
      </code>
      table. For more information,
          see
      <a class="xref" href="innodb-persistent-stats.html" title="17.8.10.1 Configuring Persistent Optimizer Statistics Parameters">
       Section 17.8.10.1, “Configuring Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       Setting a high value for
       <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
        <code class="literal">
         innodb_stats_persistent_sample_pages
        </code>
       </a>
       could result in lengthy
       <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
        <code class="literal">
         ANALYZE
            TABLE
        </code>
       </a>
       execution time. To estimate the number of
            database pages accessed by
       <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
        <code class="literal">
         ANALYZE
            TABLE
        </code>
       </a>
       , see
       <a class="xref" href="innodb-analyze-table-complexity.html" title="17.8.10.3 Estimating ANALYZE TABLE Complexity for InnoDB Tables">
        Section 17.8.10.3, “Estimating ANALYZE TABLE Complexity for InnoDB Tables”
       </a>
       .
      </p>
     </div>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
       <code class="literal">
        innodb_stats_persistent_sample_pages
       </code>
      </a>
      only applies when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      is
          enabled for a table; when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      is
          disabled,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
       <code class="literal">
        innodb_stats_transient_sample_pages
       </code>
      </a>
      applies instead.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_stats_transient_sample_pages">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
       <code class="literal">
        innodb_stats_transient_sample_pages
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152232384">
     </a>
     <a class="indexterm" name="idm46045152231376">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_stats_transient_sample_pages">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-stats-transient-sample-pages=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
            innodb_stats_transient_sample_pages
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           8
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           18446744073709551615
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of index
      <a class="link" href="glossary.html#glos_page" title="page">
       pages
      </a>
      to
          sample when estimating
      <a class="link" href="glossary.html#glos_cardinality" title="cardinality">
       cardinality
      </a>
      and other
      <a class="link" href="glossary.html#glos_statistics" title="statistics">
       statistics
      </a>
      for an
          indexed column, such as those calculated by
      <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
       <code class="literal">
        ANALYZE TABLE
       </code>
      </a>
      . The default
          value is 8. Increasing the value improves the accuracy of
          index statistics, which can improve the
      <a class="link" href="glossary.html#glos_query_execution_plan" title="query execution plan">
       query execution
          plan
      </a>
      , at the expense of increased I/O when opening an
      <code class="literal">
       InnoDB
      </code>
      table or recalculating statistics.
          For more information, see
      <a class="xref" href="innodb-statistics-estimation.html" title="17.8.10.2 Configuring Non-Persistent Optimizer Statistics Parameters">
       Section 17.8.10.2, “Configuring Non-Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       Setting a high value for
       <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
        <code class="literal">
         innodb_stats_transient_sample_pages
        </code>
       </a>
       could result in lengthy
       <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
        <code class="literal">
         ANALYZE
            TABLE
        </code>
       </a>
       execution time. To estimate the number of
            database pages accessed by
       <a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
        <code class="literal">
         ANALYZE
            TABLE
        </code>
       </a>
       , see
       <a class="xref" href="innodb-analyze-table-complexity.html" title="17.8.10.3 Estimating ANALYZE TABLE Complexity for InnoDB Tables">
        Section 17.8.10.3, “Estimating ANALYZE TABLE Complexity for InnoDB Tables”
       </a>
       .
      </p>
     </div>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_transient_sample_pages">
       <code class="literal">
        innodb_stats_transient_sample_pages
       </code>
      </a>
      only applies when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      is
          disabled for a table; when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent">
       <code class="literal">
        innodb_stats_persistent
       </code>
      </a>
      is
          enabled,
      <a class="link" href="innodb-parameters.html#sysvar_innodb_stats_persistent_sample_pages">
       <code class="literal">
        innodb_stats_persistent_sample_pages
       </code>
      </a>
      applies instead. Takes the place of
      <code class="literal">
       innodb_stats_sample_pages
      </code>
      that was removed
          in MySQL 8.0. For more information, see
      <a class="xref" href="innodb-statistics-estimation.html" title="17.8.10.2 Configuring Non-Persistent Optimizer Statistics Parameters">
       Section 17.8.10.2, “Configuring Non-Persistent Optimizer Statistics Parameters”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_status_output">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output">
       <code class="literal">
        innodb_status_output
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152188688">
     </a>
     <a class="indexterm" name="idm46045152187680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_status_output">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-status-output[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output">
            innodb_status_output
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables or disables periodic output for the standard
      <code class="literal">
       InnoDB
      </code>
      Monitor. Also used in combination
          with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output_locks">
       <code class="literal">
        innodb_status_output_locks
       </code>
      </a>
      to
          enable or disable periodic output for the
      <code class="literal">
       InnoDB
      </code>
      Lock Monitor. For more information,
          see
      <a class="xref" href="innodb-enabling-monitors.html" title="17.17.2 Enabling InnoDB Monitors">
       Section 17.17.2, “Enabling InnoDB Monitors”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_status_output_locks">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output_locks">
       <code class="literal">
        innodb_status_output_locks
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152161728">
     </a>
     <a class="indexterm" name="idm46045152160720">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_status_output_locks">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-status-output-locks[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_status_output_locks">
            innodb_status_output_locks
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables or disables the
      <code class="literal">
       InnoDB
      </code>
      Lock
          Monitor. When enabled, the
      <code class="literal">
       InnoDB
      </code>
      Lock
          Monitor prints additional information about locks in
      <code class="literal">
       SHOW ENGINE INNODB STATUS
      </code>
      output and in
          periodic output printed to the MySQL error log. Periodic
          output for the
      <code class="literal">
       InnoDB
      </code>
      Lock Monitor is
          printed as part of the standard
      <code class="literal">
       InnoDB
      </code>
      Monitor output. The standard
      <code class="literal">
       InnoDB
      </code>
      Monitor
          must therefore be enabled for the
      <code class="literal">
       InnoDB
      </code>
      Lock Monitor to print data to the MySQL error log
          periodically. For more information, see
      <a class="xref" href="innodb-enabling-monitors.html" title="17.17.2 Enabling InnoDB Monitors">
       Section 17.17.2, “Enabling InnoDB Monitors”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_strict_mode">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
       <code class="literal">
        innodb_strict_mode
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152132448">
     </a>
     <a class="indexterm" name="idm46045152131440">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_strict_mode">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-strict-mode[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
            innodb_strict_mode
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      When
      <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
       <code class="literal">
        innodb_strict_mode
       </code>
      </a>
      is
          enabled,
      <code class="literal">
       InnoDB
      </code>
      returns errors rather than
          warnings when checking for invalid or incompatible table
          options.
     </p>
     <p>
      It checks that
      <code class="literal">
       KEY_BLOCK_SIZE
      </code>
      ,
      <code class="literal">
       ROW_FORMAT
      </code>
      ,
      <code class="literal">
       DATA
          DIRECTORY
      </code>
      ,
      <code class="literal">
       TEMPORARY
      </code>
      , and
      <code class="literal">
       TABLESPACE
      </code>
      options are compatible with each
          other and other settings.
     </p>
     <p>
      <code class="literal">
       innodb_strict_mode=ON
      </code>
      also enables a row
          size check when creating or altering a table, to prevent
      <code class="literal">
       INSERT
      </code>
      or
      <code class="literal">
       UPDATE
      </code>
      from
          failing due to the record being too large for the selected
          page size.
      <code class="literal">
      </code>
     </p>
     <p>
      You can enable or disable
      <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
       <code class="literal">
        innodb_strict_mode
       </code>
      </a>
      on the
          command line when starting
      <code class="literal">
       mysqld
      </code>
      , or in a
          MySQL
      <a class="link" href="glossary.html#glos_configuration_file" title="configuration file">
       configuration
          file
      </a>
      . You can also enable or disable
      <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
       <code class="literal">
        innodb_strict_mode
       </code>
      </a>
      at runtime
          with the statement
      <code class="literal">
       SET [GLOBAL|SESSION]
          innodb_strict_mode=
       <em class="replaceable">
        <code>
         mode
        </code>
       </em>
      </code>
      ,
          where
      <code class="literal">
       <em class="replaceable">
        <code>
         mode
        </code>
       </em>
      </code>
      is
          either
      <code class="literal">
       ON
      </code>
      or
      <code class="literal">
       OFF
      </code>
      .
          Changing the
      <code class="literal">
       GLOBAL
      </code>
      setting requires
          privileges sufficient to set global system variables (see
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      ) and affects the
          operation of all clients that subsequently connect. Any client
          can change the
      <code class="literal">
       SESSION
      </code>
      setting for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_strict_mode">
       <code class="literal">
        innodb_strict_mode
       </code>
      </a>
      , and the
          setting affects only that client.
     </p>
     <p>
      Setting the session value of this system variable is a
          restricted operation. The session user must have privileges
          sufficient to set restricted session variables. See
      <a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
       Section 7.1.9.1, “System Variable Privileges”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_sync_array_size">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_array_size">
       <code class="literal">
        innodb_sync_array_size
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152089488">
     </a>
     <a class="indexterm" name="idm46045152088480">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_sync_array_size">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-sync-array-size=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_array_size">
            innodb_sync_array_size
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1024
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the size of the mutex/lock wait array. Increasing the
          value splits the internal data structure used to coordinate
          threads, for higher concurrency in workloads with large
          numbers of waiting threads. This setting must be configured
          when the MySQL instance is starting up, and cannot be changed
          afterward. Increasing the value is recommended for workloads
          that frequently produce a large number of waiting threads,
          typically greater than 768.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_sync_spin_loops">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_spin_loops">
       <code class="literal">
        innodb_sync_spin_loops
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152060256">
     </a>
     <a class="indexterm" name="idm46045152059248">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_sync_spin_loops">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-sync-spin-loops=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_spin_loops">
            innodb_sync_spin_loops
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           30
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           4294967295
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of times a thread waits for an
      <code class="literal">
       InnoDB
      </code>
      mutex to be freed before the thread
          is suspended.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_sync_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_debug">
       <code class="literal">
        innodb_sync_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152030800">
     </a>
     <a class="indexterm" name="idm46045152029792">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_sync_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-sync-debug[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_sync_debug">
            innodb_sync_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Enables sync debug checking for the
      <code class="literal">
       InnoDB
      </code>
      storage engine. This option is only available if debugging
          support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_table_locks">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_table_locks">
       <code class="literal">
        innodb_table_locks
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045152004688">
     </a>
     <a class="indexterm" name="idm46045152003680">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_table_locks">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-table-locks[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_table_locks">
            innodb_table_locks
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      If
      <a class="link" href="server-system-variables.html#sysvar_autocommit">
       <code class="literal">
        autocommit = 0
       </code>
      </a>
      ,
      <code class="literal">
       InnoDB
      </code>
      honors
      <a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
       <code class="literal">
        LOCK
          TABLES
       </code>
      </a>
      ; MySQL does not return from
      <code class="literal">
       LOCK
          TABLES ... WRITE
      </code>
      until all other threads have
          released all their locks to the table. The default value of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_table_locks">
       <code class="literal">
        innodb_table_locks
       </code>
      </a>
      is 1,
          which means that
      <a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
       <code class="literal">
        LOCK TABLES
       </code>
      </a>
      causes InnoDB to lock a table internally if
      <a class="link" href="server-system-variables.html#sysvar_autocommit">
       <code class="literal">
        autocommit = 0
       </code>
      </a>
      .
     </p>
     <p>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_table_locks">
       <code class="literal">
        innodb_table_locks = 0
       </code>
      </a>
      has no
          effect for tables locked explicitly with
      <a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
       <code class="literal">
        LOCK TABLES ...
          WRITE
       </code>
      </a>
      . It does have an effect for tables locked for
          read or write by
      <a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
       <code class="literal">
        LOCK TABLES ...
          WRITE
       </code>
      </a>
      implicitly (for example, through triggers) or
          by
      <a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
       <code class="literal">
        LOCK TABLES
          ... READ
       </code>
      </a>
      .
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-locking-transaction-model.html" title="17.7 InnoDB Locking and Transaction Model">
       Section 17.7, “InnoDB Locking and Transaction Model”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_temp_data_file_path">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
       <code class="literal">
        innodb_temp_data_file_path
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151968816">
     </a>
     <a class="indexterm" name="idm46045151967808">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_temp_data_file_path">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-temp-data-file-path=file_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
            innodb_temp_data_file_path
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          String
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ibtmp1:12M:autoextend
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the relative path, name, size, and attributes of
          global temporary tablespace data files. The global temporary
          tablespace stores rollback segments for changes made to
          user-created temporary tables.
     </p>
     <p>
      If no value is specified for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
       <code class="literal">
        innodb_temp_data_file_path
       </code>
      </a>
      ,
          the default behavior is to create a single auto-extending data
          file named
      <code class="filename">
       ibtmp1
      </code>
      in the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
      directory. The initial file size is slightly larger than 12MB.
     </p>
     <p>
      The syntax for a global temporary tablespace data file
          specification includes the file name, file size, and
      <code class="literal">
       autoextend
      </code>
      and
      <code class="literal">
       max
      </code>
      attributes:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa16657423"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none"><em class="replaceable">file_name</em>:<em class="replaceable">file_size</em>[:autoextend[:max:<em class="replaceable">max_file_size</em>]]</code></pre>
     </div>
     <p>
      The global temporary tablespace data file cannot have the same
          name as another
      <code class="literal">
       InnoDB
      </code>
      data file. Any
          inability or error creating the global temporary tablespace
          data file is treated as fatal and server startup is refused.
     </p>
     <p>
      File sizes are specified in KB, MB, or GB by appending
      <code class="literal">
       K
      </code>
      ,
      <code class="literal">
       M
      </code>
      or
      <code class="literal">
       G
      </code>
      to the size value. The sum of file sizes
          must be slightly larger than 12MB.
     </p>
     <p>
      The size limit of individual files is determined by the
          operating system. File size can be more than 4GB on operating
          systems that support large files. Use of raw disk partitions
          for global temporary tablespace data files is not supported.
     </p>
     <p>
      The
      <code class="literal">
       autoextend
      </code>
      and
      <code class="literal">
       max
      </code>
      attributes can be used only for the data file specified last
          in the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
       <code class="literal">
        innodb_temp_data_file_path
       </code>
      </a>
      setting. For example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-ini"><div class="docs-select-all right" id="sa43730906"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">innodb_temp_data_file_path</span><span class="token attr-value"><span class="token punctuation">=</span>ibtmp1:50M;ibtmp2:12M:autoextend:max:500M</span></code></pre>
     </div>
     <p>
      The
      <code class="literal">
       autoextend
      </code>
      option causes the data file
          to automatically increase in size when it runs out of free
          space. The
      <code class="literal">
       autoextend
      </code>
      increment is 64MB by
          default. To modify the increment, change the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_autoextend_increment">
       <code class="literal">
        innodb_autoextend_increment
       </code>
      </a>
      variable setting.
     </p>
     <p>
      The directory path for global temporary tablespace data files
          is formed by concatenating the paths defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_data_home_dir">
       <code class="literal">
        innodb_data_home_dir
       </code>
      </a>
      and
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
       <code class="literal">
        innodb_temp_data_file_path
       </code>
      </a>
      .
     </p>
     <p>
      Before running
      <code class="literal">
       InnoDB
      </code>
      in read-only mode,
          set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_data_file_path">
       <code class="literal">
        innodb_temp_data_file_path
       </code>
      </a>
      to
          a location outside of the data directory. The path must be
          relative to the data directory. For example:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa54676602"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token constant">--innodb-temp-data-file-path</span><span class="token attr-value"><span class="token punctuation">=</span>../../../tmp/ibtmp1:12M:autoextend</span></code></pre>
     </div>
     <p>
      For more information, see
      <a class="xref" href="innodb-temporary-tablespace.html#innodb-global-temporary-tablespace" title="Global Temporary Tablespace">
       Global Temporary Tablespace
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_temp_tablespaces_dir">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_tablespaces_dir">
       <code class="literal">
        innodb_temp_tablespaces_dir
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151920192">
     </a>
     <a class="indexterm" name="idm46045151919184">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_temp_tablespaces_dir">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-temp-tablespaces-dir=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_temp_tablespaces_dir">
            innodb_temp_tablespaces_dir
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           #innodb_temp
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the location where
      <code class="literal">
       InnoDB
      </code>
      creates a
          pool of session temporary tablespaces at startup. The default
          location is the
      <code class="filename">
       #innodb_temp
      </code>
      directory in
          the data directory. A fully qualified path or path relative to
          the data directory is permitted.
     </p>
     <p>
      Session temporary tablespaces always store user-created
          temporary tables and internal temporary tables created by the
          optimizer using
      <code class="literal">
       InnoDB
      </code>
      . (Previously, the
          on-disk storage engine for internal temporary tables was
          determined by the
      <a class="ulink" href="/doc/refman/8.0/en/server-system-variables.html#sysvar_internal_tmp_disk_storage_engine" target="_top">
       <code class="literal">
        internal_tmp_disk_storage_engine
       </code>
      </a>
      system variable, which is no longer supported. See
      <a class="xref" href="internal-temporary-tables.html#internal-temporary-tables-engines-disk" title="Storage Engine for On-Disk Internal Temporary Tables">
       Storage Engine for On-Disk Internal Temporary Tables
      </a>
      .)
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-temporary-tablespace.html#innodb-session-temporary-tablespaces" title="Session Temporary Tablespaces">
       Session Temporary Tablespaces
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_thread_concurrency">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151890768">
     </a>
     <a class="indexterm" name="idm46045151889760">
     </a>
     <a class="indexterm" name="idm46045151888368">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_thread_concurrency">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-thread-concurrency=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
            innodb_thread_concurrency
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the maximum number of threads permitted inside of
      <code class="literal">
       InnoDB
      </code>
      . A value of 0 (the default) is
          interpreted as infinite concurrency (no limit). This variable
          is intended for performance tuning on high concurrency
          systems.
     </p>
     <p>
      <code class="literal">
       InnoDB
      </code>
      tries to keep the number of threads
          inside
      <code class="literal">
       InnoDB
      </code>
      less than or equal to the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      limit. Threads waiting for locks are not counted in the number
          of concurrently executing threads.
     </p>
     <p>
      The correct setting depends on workload and computing
          environment. Consider setting this variable if your MySQL
          instance shares CPU resources with other applications or if
          your workload or number of concurrent users is growing. Test a
          range of values to determine the setting that provides the
          best performance.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      is
          a dynamic variable, which permits experimenting with different
          settings on a live test system. If a particular setting
          performs poorly, you can quickly set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
       <code class="literal">
        innodb_thread_concurrency
       </code>
      </a>
      back to 0.
     </p>
     <p>
      Use the following guidelines to help find and maintain an
          appropriate setting:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         If the number of concurrent user threads for a workload is
              consistently small and does not affect performance, set
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency=0
          </code>
         </a>
         (no limit).
        </p>
       </li>
       <li class="listitem">
        <p>
         If your workload is consistently heavy or occasionally
              spikes, set an
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         value and adjust it until you find the number of threads
              that provides the best performance. For example, suppose
              that your system typically has 40 to 50 users, but
              periodically the number increases to 60, 70, or more.
              Through testing, you find that performance remains largely
              stable with a limit of 80 concurrent users. In this case,
              set
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         to 80.
        </p>
       </li>
       <li class="listitem">
        <p>
         If you do not want
         <code class="literal">
          InnoDB
         </code>
         to use more
              than a certain number of virtual CPUs for user threads (20
              virtual CPUs, for example), set
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         to this number (or possibly lower, depending on
              performance testing). If your goal is to isolate MySQL
              from other applications, consider binding the
         <code class="literal">
          mysqld
         </code>
         process exclusively to the
              virtual CPUs. Be aware, however, that exclusive binding
              can result in non-optimal hardware usage if the
         <code class="literal">
          mysqld
         </code>
         process is not consistently
              busy. In this case, you can bind the
         <code class="literal">
          mysqld
         </code>
         process to the virtual CPUs but
              allow other applications to use some or all of the virtual
              CPUs.
        </p>
        <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
         <div class="admon-title">
          Note
         </div>
         <p>
          From an operating system perspective, using a resource
                management solution to manage how CPU time is shared
                among applications may be preferable to binding the
          <code class="literal">
           mysqld
          </code>
          process. For example, you
                could assign 90% of virtual CPU time to a given
                application while other critical processes
          <span class="emphasis">
           <em>
            are
                not
           </em>
          </span>
          running, and scale that value back to 40%
                when other critical processes
          <span class="emphasis">
           <em>
            are
           </em>
          </span>
          running.
         </p>
        </div>
       </li>
       <li class="listitem">
        <p>
         In some cases, the optimal
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         setting can be smaller than the number of virtual CPUs.
        </p>
       </li>
       <li class="listitem">
        <p>
         An
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         value that is too high can cause performance regression
              due to increased contention on system internals and
              resources.
        </p>
       </li>
       <li class="listitem">
        <p>
         Monitor and analyze your system regularly. Changes to
              workload, number of users, or computing environment may
              require that you adjust the
         <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_concurrency">
          <code class="literal">
           innodb_thread_concurrency
          </code>
         </a>
         setting.
        </p>
       </li>
      </ul>
     </div>
     <p>
      A value of 0 disables the
      <code class="literal">
       queries inside
          InnoDB
      </code>
      and
      <code class="literal">
       queries in queue
      </code>
      counters in the
      <code class="literal">
       ROW OPERATIONS
      </code>
      section of
      <code class="literal">
       SHOW ENGINE INNODB STATUS
      </code>
      output.
     </p>
     <p>
      For related information, see
      <a class="xref" href="innodb-performance-thread_concurrency.html" title="17.8.4 Configuring Thread Concurrency for InnoDB">
       Section 17.8.4, “Configuring Thread Concurrency for InnoDB”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_thread_sleep_delay">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
       <code class="literal">
        innodb_thread_sleep_delay
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151830448">
     </a>
     <a class="indexterm" name="idm46045151829440">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_thread_sleep_delay">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-thread-sleep-delay=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
            innodb_thread_sleep_delay
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           10000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1000000
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Unit
         </th>
         <td>
          microseconds
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      How long
      <code class="literal">
       InnoDB
      </code>
      threads sleep before
          joining the
      <code class="literal">
       InnoDB
      </code>
      queue, in microseconds.
          The default value is 10000. A value of 0 disables sleep. You
          can set
      <a class="link" href="innodb-parameters.html#sysvar_innodb_adaptive_max_sleep_delay">
       <code class="literal">
        innodb_adaptive_max_sleep_delay
       </code>
      </a>
      to the highest value you would allow for
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
       <code class="literal">
        innodb_thread_sleep_delay
       </code>
      </a>
      ,
          and
      <code class="literal">
       InnoDB
      </code>
      automatically adjusts
      <a class="link" href="innodb-parameters.html#sysvar_innodb_thread_sleep_delay">
       <code class="literal">
        innodb_thread_sleep_delay
       </code>
      </a>
      up
          or down depending on current thread-scheduling activity. This
          dynamic adjustment helps the thread scheduling mechanism to
          work smoothly during times when the system is lightly loaded
          or when it is operating near full capacity.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-performance-thread_concurrency.html" title="17.8.4 Configuring Thread Concurrency for InnoDB">
       Section 17.8.4, “Configuring Thread Concurrency for InnoDB”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_tmpdir">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151793552">
     </a>
     <a class="indexterm" name="idm46045151792544">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_tmpdir">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-tmpdir=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
            innodb_tmpdir
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global, Session
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           NULL
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Used to define an alternate directory for temporary sort files
          created during online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER
          TABLE
       </code>
      </a>
      operations that rebuild the table.
     </p>
     <p>
      Online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      operations
          that rebuild the table also create an
      <span class="emphasis">
       <em>
        intermediate
       </em>
      </span>
      table file in the same
          directory as the original table. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      option is not
          applicable to intermediate table files.
     </p>
     <p>
      A valid value is any directory path other than the MySQL data
          directory path. If the value is NULL (the default), temporary
          files are created MySQL temporary directory
          (
      <code class="literal">
       $TMPDIR
      </code>
      on Unix,
      <code class="literal">
       %TEMP%
      </code>
      on Windows, or the directory specified by the
      <a class="link" href="server-system-variables.html#sysvar_tmpdir">
       <code class="literal">
        --tmpdir
       </code>
      </a>
      configuration
          option). If a directory is specified, existence of the
          directory and permissions are only checked when
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      is configured
          using a
      <a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
       <code class="literal">
        SET
       </code>
      </a>
      statement. If a symlink is provided in a directory string, the
          symlink is resolved and stored as an absolute path. The path
          should not exceed 512 bytes. An online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      operation reports
          an error if
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      is
          set to an invalid directory.
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      overrides the
          MySQL
      <a class="link" href="server-system-variables.html#sysvar_tmpdir">
       <code class="literal">
        tmpdir
       </code>
      </a>
      setting but only
          for online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      operations.
     </p>
     <p>
      The
      <code class="literal">
       FILE
      </code>
      privilege is required to configure
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      .
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      option was
          introduced to help avoid overflowing a temporary file
          directory located on a
      <code class="literal">
       tmpfs
      </code>
      file system.
          Such overflows could occur as a result of large temporary sort
          files created during online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER
          TABLE
       </code>
      </a>
      operations that rebuild the table.
     </p>
     <p>
      In replication environments, only consider replicating the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      setting if all
          servers have the same operating system environment. Otherwise,
          replicating the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      setting could result in a replication failure when running
          online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER TABLE
       </code>
      </a>
      operations
          that rebuild the table. If server operating environments
          differ, it is recommended that you configure
      <a class="link" href="innodb-parameters.html#sysvar_innodb_tmpdir">
       <code class="literal">
        innodb_tmpdir
       </code>
      </a>
      on each server
          individually.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-online-ddl-space-requirements.html" title="17.12.3 Online DDL Space Requirements">
       Section 17.12.3, “Online DDL Space Requirements”
      </a>
      . For
          information about online
      <a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
       <code class="literal">
        ALTER
          TABLE
       </code>
      </a>
      operations, see
      <a class="xref" href="innodb-online-ddl.html" title="17.12 InnoDB and Online DDL">
       Section 17.12, “InnoDB and Online DDL”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_trx_purge_view_update_only_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_purge_view_update_only_debug">
       <code class="literal">
        innodb_trx_purge_view_update_only_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151742720">
     </a>
     <a class="indexterm" name="idm46045151741712">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_trx_purge_view_update_only_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-trx-purge-view-update-only-debug[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_purge_view_update_only_debug">
            innodb_trx_purge_view_update_only_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Pauses purging of delete-marked records while allowing the
          purge view to be updated. This option artificially creates a
          situation in which the purge view is updated but purges have
          not yet been performed. This option is only available if
          debugging support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_trx_rseg_n_slots_debug">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_rseg_n_slots_debug">
       <code class="literal">
        innodb_trx_rseg_n_slots_debug
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151717024">
     </a>
     <a class="indexterm" name="idm46045151716016">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_trx_rseg_n_slots_debug">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-trx-rseg-n-slots-debug=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_trx_rseg_n_slots_debug">
            innodb_trx_rseg_n_slots_debug
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           0
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           1024
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Sets a debug flag that limits
      <code class="literal">
       TRX_RSEG_N_SLOTS
      </code>
      to a given value for the
      <code class="literal">
       trx_rsegf_undo_find_free
      </code>
      function that
          looks for free slots for undo log segments. This option is
          only available if debugging support is compiled in using the
      <a class="link" href="source-configuration-options.html#option_cmake_with_debug">
       <code class="option">
        WITH_DEBUG
       </code>
      </a>
      <span class="command">
       <strong>
        CMake
       </strong>
      </span>
      option.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_undo_directory">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
       <code class="literal">
        innodb_undo_directory
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151685552">
     </a>
     <a class="indexterm" name="idm46045151684544">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_undo_directory">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-undo-directory=dir_name
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
            innodb_undo_directory
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Directory name
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The path where
      <code class="literal">
       InnoDB
      </code>
      creates undo
          tablespaces. Typically used to place undo tablespaces on a
          different storage device.
     </p>
     <p>
      There is no default value (it is NULL). If the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
       <code class="literal">
        innodb_undo_directory
       </code>
      </a>
      variable is undefined, undo tablespaces are created in the
          data directory.
     </p>
     <p>
      The default undo tablespaces
          (
      <code class="filename">
       innodb_undo_001
      </code>
      and
      <code class="filename">
       innodb_undo_002
      </code>
      ) created when the MySQL
          instance is initialized always reside in the directory defined
          by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
       <code class="literal">
        innodb_undo_directory
       </code>
      </a>
      variable.
     </p>
     <p>
      Undo tablespaces created using
      <a class="link" href="create-tablespace.html" title="15.1.21 CREATE TABLESPACE Statement">
       <code class="literal">
        CREATE UNDO
          TABLESPACE
       </code>
      </a>
      syntax are created in the directory
          defined by the
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_directory">
       <code class="literal">
        innodb_undo_directory
       </code>
      </a>
      variable if a different path is not specified.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-undo-tablespaces.html" title="17.6.3.4 Undo Tablespaces">
       Section 17.6.3.4, “Undo Tablespaces”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_undo_log_encrypt">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_encrypt">
       <code class="literal">
        innodb_undo_log_encrypt
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151655408">
     </a>
     <a class="indexterm" name="idm46045151654400">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_undo_log_encrypt">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-undo-log-encrypt[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_encrypt">
            innodb_undo_log_encrypt
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           OFF
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls encryption of undo log data for tables encrypted
          using the
      <code class="literal">
       InnoDB
      </code>
      <a class="link" href="innodb-data-encryption.html" title="17.13 InnoDB Data-at-Rest Encryption">
       data-at-rest encryption
          feature
      </a>
      . Only applies to undo logs that reside in
          separate
      <a class="link" href="glossary.html#glos_undo_tablespace" title="undo tablespace">
       undo
          tablespaces
      </a>
      . See
      <a class="xref" href="innodb-undo-tablespaces.html" title="17.6.3.4 Undo Tablespaces">
       Section 17.6.3.4, “Undo Tablespaces”
      </a>
      . Encryption is not
          supported for undo log data that resides in the system
          tablespace. For more information, see
      <a class="xref" href="innodb-data-encryption.html#innodb-data-encryption-undo-log" title="Undo Log Encryption">
       Undo Log Encryption
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_undo_log_truncate">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_truncate">
       <code class="literal">
        innodb_undo_log_truncate
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151628224">
     </a>
     <a class="indexterm" name="idm46045151627216">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_undo_log_truncate">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-undo-log-truncate[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_log_truncate">
            innodb_undo_log_truncate
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      When enabled, undo tablespaces that exceed the threshold value
          defined by
      <a class="link" href="innodb-parameters.html#sysvar_innodb_max_undo_log_size">
       <code class="literal">
        innodb_max_undo_log_size
       </code>
      </a>
      are
          marked for truncation. Only undo tablespaces can be truncated.
          Truncating undo logs that reside in the system tablespace is
          not supported. For truncation to occur, there must be at least
          two undo tablespaces.
     </p>
     <p>
      The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_purge_rseg_truncate_frequency">
       <code class="literal">
        innodb_purge_rseg_truncate_frequency
       </code>
      </a>
      variable can be used to expedite truncation of undo
          tablespaces.
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-undo-tablespaces.html#truncate-undo-tablespace" title="Truncating Undo Tablespaces">
       Truncating Undo Tablespaces
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_undo_tablespaces">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_tablespaces">
       <code class="literal">
        innodb_undo_tablespaces
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151600496">
     </a>
     <a class="indexterm" name="idm46045151599488">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_undo_tablespaces">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-undo-tablespaces=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Deprecated
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_tablespaces">
            innodb_undo_tablespaces
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           2
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           127
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Defines the number of
      <a class="link" href="glossary.html#glos_undo_tablespace" title="undo tablespace">
       undo tablespaces
      </a>
      used by
      <code class="literal">
       InnoDB
      </code>
      . The default and minimum
          value is 2.
     </p>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       The
       <a class="link" href="innodb-parameters.html#sysvar_innodb_undo_tablespaces">
        <code class="literal">
         innodb_undo_tablespaces
        </code>
       </a>
       variable is deprecated; setting it has no effect. You should
            expect it to be removed in a future MySQL release.
      </p>
     </div>
     <p>
      For more information, see
      <a class="xref" href="innodb-undo-tablespaces.html" title="17.6.3.4 Undo Tablespaces">
       Section 17.6.3.4, “Undo Tablespaces”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_use_fdatasync">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
       <code class="literal">
        innodb_use_fdatasync
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151565712">
     </a>
     <a class="indexterm" name="idm46045151564704">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_use_fdatasync">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-use-fdatasync[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
            innodb_use_fdatasync
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          Yes
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      On platforms that support
      <code class="literal">
       fdatasync()
      </code>
      system calls, having
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
       <code class="literal">
        innodb_use_fdatasync
       </code>
      </a>
      enabled
          permits using
      <code class="literal">
       fdatasync()
      </code>
      instead of
      <code class="literal">
       fsync()
      </code>
      system calls for operating system
          flushes. An
      <code class="literal">
       fdatasync()
      </code>
      call does not flush
          changes to file metadata unless required for subsequent data
          retrieval, providing a potential performance benefit.
     </p>
     <p>
      A subset of
      <a class="link" href="innodb-parameters.html#sysvar_innodb_flush_method">
       <code class="literal">
        innodb_flush_method
       </code>
      </a>
      settings
          such as
      <code class="literal">
       fsync
      </code>
      ,
      <code class="literal">
       O_DSYNC
      </code>
      ,
          and
      <code class="literal">
       O_DIRECT
      </code>
      use
      <code class="literal">
       fsync()
      </code>
      system calls. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_fdatasync">
       <code class="literal">
        innodb_use_fdatasync
       </code>
      </a>
      variable
          is applicable when using those settings.
     </p>
     <p>
      Before MySQL 8.4, this option was disabled by default.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_use_native_aio">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_native_aio">
       <code class="literal">
        innodb_use_native_aio
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151532576">
     </a>
     <a class="indexterm" name="idm46045151531568">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_use_native_aio">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-use-native-aio[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_use_native_aio">
            innodb_use_native_aio
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Specifies whether to use the
      <a class="link" href="glossary.html#glos_asynchronous_io" title="asynchronous I/O">
       asynchronous I/O
      </a>
      subsystem. This variable cannot be changed while the server is
          running. Normally, you do not need to configure this option,
          because it is enabled by default.
     </p>
     <p>
      This feature improves the scalability of heavily I/O-bound
          systems, which typically show many pending reads/writes in
      <code class="literal">
       SHOW ENGINE INNODB STATUS
      </code>
      output.
     </p>
     <p>
      Running with a large number of
      <code class="literal">
       InnoDB
      </code>
      I/O
          threads, and especially running multiple such instances on the
          same server machine, can exceed capacity limits on Linux
          systems. In this case, you may receive the following error:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa14581038"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">EAGAIN<span class="token punctuation">:</span> The specified maxevents exceeds the user's limit of available events<span class="token punctuation">.</span></code></pre>
     </div>
     <p>
      You can typically address this error by writing a higher limit
          to
      <code class="literal">
       /proc/sys/fs/aio-max-nr
      </code>
      .
     </p>
     <p>
      However, if a problem with the asynchronous I/O subsystem in
          the OS prevents
      <code class="literal">
       InnoDB
      </code>
      from starting, you
          can start the server with
      <a class="link" href="innodb-parameters.html#sysvar_innodb_use_native_aio">
       <code class="literal">
        innodb_use_native_aio=0
       </code>
      </a>
      . This
          option may also be disabled automatically during startup if
      <code class="literal">
       InnoDB
      </code>
      detects a potential problem such as
          a combination of
      <code class="literal">
       tmpdir
      </code>
      location,
      <code class="literal">
       tmpfs
      </code>
      file system, and Linux kernel that
          does not support AIO on
      <code class="literal">
       tmpfs
      </code>
      .
     </p>
     <p>
      For more information, see
      <a class="xref" href="innodb-linux-native-aio.html" title="17.8.6 Using Asynchronous I/O on Linux">
       Section 17.8.6, “Using Asynchronous I/O on Linux”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_validate_tablespace_paths">
      </a>
      <code class="literal">
       innodb_validate_tablespace_paths
      </code>
     </p>
     <a class="indexterm" name="idm46045151497840">
     </a>
     <a class="indexterm" name="idm46045151496832">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_validate_tablespace_paths">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-validate-tablespace-paths[={OFF|ON}]
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_validate_tablespace_paths">
            innodb_validate_tablespace_paths
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Boolean
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           ON
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      Controls tablespace file path validation. At startup,
      <code class="literal">
       InnoDB
      </code>
      validates the paths of known
          tablespace files against tablespace file paths stored in the
          data dictionary in case tablespace files have been moved to a
          different location. The
      <a class="link" href="innodb-parameters.html#sysvar_innodb_validate_tablespace_paths">
       <code class="literal">
        innodb_validate_tablespace_paths
       </code>
      </a>
      variable permits disabling tablespace path validation. This
          feature is intended for environments where tablespaces files
          are not moved. Disabling path validation improves startup time
          on systems with a large number of tablespace files.
     </p>
     <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Warning
      </div>
      <p>
       Starting the server with tablespace path validation disabled
            after moving tablespace files can lead to undefined
            behavior.
      </p>
     </div>
     <p>
      For more information, see
      <a class="xref" href="innodb-disabling-tablespace-path-validation.html" title="17.6.3.7 Disabling Tablespace Path Validation">
       Section 17.6.3.7, “Disabling Tablespace Path Validation”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_version">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_version">
       <code class="literal">
        innodb_version
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151469776">
     </a>
     <a class="indexterm" name="idm46045151468768">
     </a>
     <p>
      The
      <code class="literal">
       InnoDB
      </code>
      version number. This is a legacy
          variable, the value is the same as the MySQL server
      <a class="link" href="server-system-variables.html#sysvar_version">
       <code class="literal">
        version
       </code>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="sysvar_innodb_write_io_threads">
      </a>
      <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
       <code class="literal">
        innodb_write_io_threads
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045151463248">
     </a>
     <a class="indexterm" name="idm46045151462240">
     </a>
     <div class="informaltable">
      <table frame="box" rules="all" summary="Properties for innodb_write_io_threads">
       <colgroup>
        <col style="width: 30%"/>
        <col style="width: 70%"/>
       </colgroup>
       <tbody>
        <tr>
         <th>
          Command-Line Format
         </th>
         <td>
          <code class="literal">
           --innodb-write-io-threads=#
          </code>
         </td>
        </tr>
        <tr>
         <th>
          System Variable
         </th>
         <td>
          <code class="literal">
           <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
            innodb_write_io_threads
           </a>
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Scope
         </th>
         <td>
          Global
         </td>
        </tr>
        <tr>
         <th>
          Dynamic
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          <a class="link" href="optimizer-hints.html#optimizer-hints-set-var" title="Variable-Setting Hint Syntax">
           <code class="literal">
            SET_VAR
           </code>
          </a>
          Hint Applies
         </th>
         <td>
          No
         </td>
        </tr>
        <tr>
         <th>
          Type
         </th>
         <td>
          Integer
         </td>
        </tr>
        <tr>
         <th>
          Default Value
         </th>
         <td>
          <code class="literal">
           4
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Minimum Value
         </th>
         <td>
          <code class="literal">
           1
          </code>
         </td>
        </tr>
        <tr>
         <th>
          Maximum Value
         </th>
         <td>
          <code class="literal">
           64
          </code>
         </td>
        </tr>
       </tbody>
      </table>
     </div>
     <p>
      The number of I/O threads for write operations in
      <code class="literal">
       InnoDB
      </code>
      . The default value is 4. Its
          counterpart for read threads is
      <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
       <code class="literal">
        innodb_read_io_threads
       </code>
      </a>
      . For
          more information, see
      <a class="xref" href="innodb-performance-multiple_io_threads.html" title="17.8.5 Configuring the Number of Background InnoDB I/O Threads">
       Section 17.8.5, “Configuring the Number of Background InnoDB I/O Threads”
      </a>
      . For
          general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
     <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
      <div class="admon-title">
       Note
      </div>
      <p>
       On Linux systems, running multiple MySQL servers (typically
            more than 12) with default settings for
       <a class="link" href="innodb-parameters.html#sysvar_innodb_read_io_threads">
        <code class="literal">
         innodb_read_io_threads
        </code>
       </a>
       ,
       <a class="link" href="innodb-parameters.html#sysvar_innodb_write_io_threads">
        <code class="literal">
         innodb_write_io_threads
        </code>
       </a>
       ,
            and the Linux
       <code class="literal">
        aio-max-nr
       </code>
       setting can
            exceed system limits. Ideally, increase the
       <code class="literal">
        aio-max-nr
       </code>
       setting; as a workaround, you
            might reduce the settings for one or both of the MySQL
            variables.
      </p>
     </div>
     <p>
      Also take into consideration the value of
      <a class="link" href="replication-options-binary-log.html#sysvar_sync_binlog">
       <code class="literal">
        sync_binlog
       </code>
      </a>
      , which controls
          synchronization of the binary log to disk.
     </p>
     <p>
      For general I/O tuning advice, see
      <a class="xref" href="optimizing-innodb-diskio.html" title="10.5.8 Optimizing InnoDB Disk I/O">
       Section 10.5.8, “Optimizing InnoDB Disk I/O”
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
 </div>
 <br/>
</div>
