<div id="docs-body">
 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h4 class="title">
      <a name="show-engine">
      </a>
      15.7.7.16 SHOW ENGINE Statement
     </h4>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045170704320">
  </a>
  <a class="indexterm" name="idm46045170703248">
  </a>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa89528081"><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">SHOW</span> <span class="token keyword">ENGINE</span> <em class="replaceable">engine_name</em> {<span class="token keyword">STATUS</span> <span class="token operator">|</span> <span class="token keyword">MUTEX</span>}</code></pre>
  </div>
  <p>
   <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
    <code class="literal">
     SHOW ENGINE
    </code>
   </a>
   displays operational
        information about a storage engine. It requires the
   <a class="link" href="privileges-provided.html#priv_process">
    <code class="literal">
     PROCESS
    </code>
   </a>
   privilege. The statement
        has these variants:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa17240958"><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">SHOW</span> <span class="token keyword">ENGINE</span> INNODB <span class="token keyword">STATUS</span>
<span class="token keyword">SHOW</span> <span class="token keyword">ENGINE</span> INNODB <span class="token keyword">MUTEX</span>
<span class="token keyword">SHOW</span> <span class="token keyword">ENGINE</span> PERFORMANCE_SCHEMA <span class="token keyword">STATUS</span></code></pre>
  </div>
  <p>
   <code class="literal">
    SHOW ENGINE INNODB STATUS
   </code>
   displays extensive
        information from the standard
   <code class="literal">
    InnoDB
   </code>
   Monitor
        about the state of the
   <code class="literal">
    InnoDB
   </code>
   storage engine.
        For information about the standard monitor and other
   <code class="literal">
    InnoDB
   </code>
   Monitors that provide information
        about
   <code class="literal">
    InnoDB
   </code>
   processing, see
   <a class="xref" href="innodb-monitors.html" title="17.17 InnoDB Monitors">
    Section 17.17, “InnoDB Monitors”
   </a>
   .
  </p>
  <p>
   <code class="literal">
    SHOW ENGINE INNODB MUTEX
   </code>
   displays
   <code class="literal">
    InnoDB
   </code>
   <a class="link" href="glossary.html#glos_mutex" title="mutex">
    mutex
   </a>
   and
   <a class="link" href="glossary.html#glos_rw_lock" title="rw-lock">
    rw-lock
   </a>
   statistics.
  </p>
  <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
   <div class="admon-title">
    Note
   </div>
   <p>
    <code class="literal">
     InnoDB
    </code>
    mutexes and rwlocks can also be
          monitored using
    <a class="link" href="performance-schema.html" title="Chapter 29 MySQL Performance Schema">
     Performance
          Schema
    </a>
    tables. See
    <a class="xref" href="monitor-innodb-mutex-waits-performance-schema.html" title="17.16.2 Monitoring InnoDB Mutex Waits Using Performance Schema">
     Section 17.16.2, “Monitoring InnoDB Mutex Waits Using Performance Schema”
    </a>
    .
   </p>
  </div>
  <p>
   Mutex statistics collection is configured dynamically using the
        following options:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      To enable the collection of mutex statistics, run:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa60743563"><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_monitor_enable<span class="token operator">=</span><span class="token string">'latch'</span><span class="token punctuation">;</span></code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      To reset mutex statistics, run:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa72948290"><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_monitor_reset<span class="token operator">=</span><span class="token string">'latch'</span><span class="token punctuation">;</span></code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      To disable the collection of mutex statistics, run:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa68186147"><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_monitor_disable<span class="token operator">=</span><span class="token string">'latch'</span><span class="token punctuation">;</span></code></pre>
     </div>
    </li>
   </ul>
  </div>
  <p>
   Collection of mutex statistics for
   <code class="literal">
    SHOW ENGINE INNODB
        MUTEX
   </code>
   can also be enabled by setting
   <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_enable">
    <code class="literal">
     innodb_monitor_enable='all'
    </code>
   </a>
   , or
        disabled by setting
   <a class="link" href="innodb-parameters.html#sysvar_innodb_monitor_disable">
    <code class="literal">
     innodb_monitor_disable='all'
    </code>
   </a>
   .
  </p>
  <p>
   <code class="literal">
    SHOW ENGINE INNODB MUTEX
   </code>
   output has these
        columns:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       Type
      </code>
     </p>
     <p>
      Always
      <code class="literal">
       InnoDB
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       Name
      </code>
     </p>
     <p>
      For mutexes, the
      <code class="literal">
       Name
      </code>
      field reports only
            the mutex name. For rwlocks, the
      <code class="literal">
       Name
      </code>
      field reports the source file where the rwlock is
            implemented, and the line number in the file where the
            rwlock is created. The line number is specific to your
            version of MySQL.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       Status
      </code>
     </p>
     <p>
      The mutex status. This field reports the number of spins,
            waits, and calls. Statistics for low-level operating system
            mutexes, which are implemented outside of
      <code class="literal">
       InnoDB
      </code>
      , are not reported.
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         <code class="literal">
          spins
         </code>
         indicates the number of spins.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          waits
         </code>
         indicates the number of mutex
                waits.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          calls
         </code>
         indicates how many times the
                mutex was requested.
        </p>
       </li>
      </ul>
     </div>
    </li>
   </ul>
  </div>
  <p>
   <code class="literal">
    SHOW ENGINE INNODB MUTEX
   </code>
   does not list
        mutexes and rw-locks for each buffer pool block, as the amount
        of output would be overwhelming on systems with a large buffer
        pool.
   <code class="literal">
    SHOW ENGINE INNODB MUTEX
   </code>
   does, however,
        print aggregate
   <code class="literal">
    BUF_BLOCK_MUTEX
   </code>
   spin, wait,
        and call values for buffer pool block mutexes and rw-locks.
   <code class="literal">
    SHOW ENGINE INNODB MUTEX
   </code>
   also does not list
        any mutexes or rw-locks that have never been waited on
        (
   <code class="literal">
    os_waits=0
   </code>
   ). Thus,
   <code class="literal">
    SHOW ENGINE
        INNODB MUTEX
   </code>
   only displays information about mutexes
        and rw-locks outside of the buffer pool that have caused at
        least one OS-level
   <a class="link" href="glossary.html#glos_wait" title="wait">
    wait
   </a>
   .
  </p>
  <p>
   Use
   <code class="literal">
    SHOW ENGINE PERFORMANCE_SCHEMA STATUS
   </code>
   to
        inspect the internal operation of the Performance Schema code:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa68892952"><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">SHOW</span> <span class="token keyword">ENGINE</span> PERFORMANCE_SCHEMA <span class="token keyword">STATUS</span>\G
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 3. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
  Type<span class="token punctuation">:</span> performance_schema
  Name<span class="token punctuation">:</span> events_waits_history.size
Status<span class="token punctuation">:</span> 76
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 4. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
  Type<span class="token punctuation">:</span> performance_schema
  Name<span class="token punctuation">:</span> events_waits_history.count
Status<span class="token punctuation">:</span> 10000
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 5. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
  Type<span class="token punctuation">:</span> performance_schema
  Name<span class="token punctuation">:</span> events_waits_history.memory
Status<span class="token punctuation">:</span> 760000
...
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 57. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
  Type<span class="token punctuation">:</span> performance_schema
  Name<span class="token punctuation">:</span> performance_schema.memory
Status<span class="token punctuation">:</span> 26459600
...</span></code></pre>
  </div>
  <p>
   This statement is intended to help the DBA understand the
        effects that different Performance Schema options have on memory
        requirements.
  </p>
  <p>
   <code class="literal">
    Name
   </code>
   values consist of two parts, which name
        an internal buffer and a buffer attribute, respectively.
        Interpret buffer names as follows:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      An internal buffer that is not exposed as a table is named
            within parentheses. Examples:
      <code class="literal">
       (pfs_cond_class).size
      </code>
      ,
      <code class="literal">
       (pfs_mutex_class).memory
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      An internal buffer that is exposed as a table in the
      <code class="literal">
       performance_schema
      </code>
      database is named
            after the table, without parentheses. Examples:
      <code class="literal">
       events_waits_history.size
      </code>
      ,
      <code class="literal">
       mutex_instances.count
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      A value that applies to the Performance Schema as a whole
            begins with
      <code class="literal">
       performance_schema
      </code>
      . Example:
      <code class="literal">
       performance_schema.memory
      </code>
      .
     </p>
    </li>
   </ul>
  </div>
  <p>
   Buffer attributes have these meanings:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       size
      </code>
      is the size of the internal record
            used by the implementation, such as the size of a row in a
            table.
      <code class="literal">
       size
      </code>
      values cannot be changed.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       count
      </code>
      is the number of internal records,
            such as the number of rows in a table.
      <code class="literal">
       count
      </code>
      values can be changed using
            Performance Schema configuration options.
     </p>
    </li>
    <li class="listitem">
     <p>
      For a table,
      <code class="literal">
       <em class="replaceable">
        <code>
         tbl_name
        </code>
       </em>
       .memory
      </code>
      is the product of
      <code class="literal">
       size
      </code>
      and
      <code class="literal">
       count
      </code>
      . For the Performance Schema as a
            whole,
      <code class="literal">
       performance_schema.memory
      </code>
      is the
            sum of all the memory used (the sum of all other
      <code class="literal">
       memory
      </code>
      values).
     </p>
    </li>
   </ul>
  </div>
  <p>
   In some cases, there is a direct relationship between a
        Performance Schema configuration parameter and a
   <code class="literal">
    SHOW
        ENGINE
   </code>
   value. For example,
   <code class="literal">
    events_waits_history_long.count
   </code>
   corresponds
        to
   <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_events_waits_history_long_size">
    <code class="literal">
     performance_schema_events_waits_history_long_size
    </code>
   </a>
   .
        In other cases, the relationship is more complex. For example,
   <code class="literal">
    events_waits_history.count
   </code>
   corresponds to
   <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_events_waits_history_size">
    <code class="literal">
     performance_schema_events_waits_history_size
    </code>
   </a>
   (the number of rows per thread) multiplied by
   <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_thread_instances">
    <code class="literal">
     performance_schema_max_thread_instances
    </code>
   </a>
   (the number of threads).
  </p>
  <p>
   <a name="show-engine-ndb-status">
   </a>
   <b>
    SHOW ENGINE NDB STATUS.
   </b>
   If the server has the
   <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
    <code class="literal">
     NDB
    </code>
   </a>
   storage
          engine enabled,
   <code class="literal">
    SHOW ENGINE NDB STATUS
   </code>
   displays cluster status information such as the number of
          connected data nodes, the cluster connectstring, and cluster
          binary log epochs, as well as counts of various Cluster API
          objects created by the MySQL Server when connected to the
          cluster. Sample output from this statement is shown here:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa61156053"><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">SHOW</span> <span class="token keyword">ENGINE</span> <span class="token keyword">NDB</span> <span class="token keyword">STATUS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Type       <span class="token punctuation">|</span> Name                  <span class="token punctuation">|</span> Status                                           <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token operator">|</span> <span class="token keyword">ndbcluster</span> <span class="token operator">|</span> <span class="token keyword">connection</span>            <span class="token operator">|</span> cluster_node_id<span class="token operator">=</span><span class="token number">7</span><span class="token punctuation">,</span>
  connected_host<span class="token operator">=</span><span class="token number">198.51</span><span class="token punctuation">.</span><span class="token number">100.103</span><span class="token punctuation">,</span> connected_port<span class="token operator">=</span><span class="token number">1186</span><span class="token punctuation">,</span> number_of_data_nodes<span class="token operator">=</span><span class="token number">4</span><span class="token punctuation">,</span>
  number_of_ready_data_nodes<span class="token operator">=</span><span class="token number">3</span><span class="token punctuation">,</span> connect_count<span class="token operator">=</span><span class="token number">0</span>                                         <span class="token operator">|</span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbTransaction        <span class="token punctuation">|</span> created=6, free=0, sizeof=212                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbOperation          <span class="token punctuation">|</span> created=8, free=8, sizeof=660                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbIndexScanOperation <span class="token punctuation">|</span> created=1, free=1, sizeof=744                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbIndexOperation     <span class="token punctuation">|</span> created=0, free=0, sizeof=664                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbRecAttr            <span class="token punctuation">|</span> created=1285, free=1285, sizeof=60               <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbApiSignal          <span class="token punctuation">|</span> created=16, free=16, sizeof=136                  <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbLabel              <span class="token punctuation">|</span> created=0, free=0, sizeof=196                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbBranch             <span class="token punctuation">|</span> created=0, free=0, sizeof=24                     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbSubroutine         <span class="token punctuation">|</span> created=0, free=0, sizeof=68                     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbCall               <span class="token punctuation">|</span> created=0, free=0, sizeof=16                     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbBlob               <span class="token punctuation">|</span> created=1, free=1, sizeof=264                    <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ndbcluster <span class="token punctuation">|</span> NdbReceiver           <span class="token punctuation">|</span> created=4, free=0, sizeof=68                     <span class="token punctuation">|</span></span>
<span class="token operator">|</span> <span class="token keyword">ndbcluster</span> <span class="token operator">|</span> <span class="token keyword">binlog</span>                <span class="token operator">|</span> latest_epoch<span class="token operator">=</span><span class="token number">155467</span><span class="token punctuation">,</span> latest_trans_epoch<span class="token operator">=</span><span class="token number">148126</span><span class="token punctuation">,</span>
  latest_received_binlog_epoch<span class="token operator">=</span><span class="token number">0</span><span class="token punctuation">,</span> latest_handled_binlog_epoch<span class="token operator">=</span><span class="token number">0</span><span class="token punctuation">,</span>
  latest_applied_binlog_epoch<span class="token operator">=</span><span class="token number">0</span>                                                         <span class="token operator">|</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
  </div>
  <p>
   The
   <code class="literal">
    Status
   </code>
   column in each of these rows
        provides information about the MySQL server's connection to
        the cluster and about the cluster binary log's status,
        respectively. The
   <code class="literal">
    Status
   </code>
   information is in
        the form of comma-delimited set of name-value pairs.
  </p>
  <p>
   The
   <code class="literal">
    connection
   </code>
   row's
   <code class="literal">
    Status
   </code>
   column contains the name-value pairs
        described in the following table.
  </p>
  <div class="informaltable">
   <table summary="Name and value pairs found in the connection row Status column in the output of the SHOW ENGINE NDB STATUS statement.">
    <colgroup>
     <col style="width: 40%"/>
     <col style="width: 60%"/>
    </colgroup>
    <thead>
     <tr>
      <th>
       Name
      </th>
      <th>
       Value
      </th>
     </tr>
    </thead>
    <tbody>
     <tr>
      <td>
       <code class="literal">
        cluster_node_id
       </code>
      </td>
      <td>
       The node ID of the MySQL server in the cluster
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        connected_host
       </code>
      </td>
      <td>
       The host name or IP address of the cluster management server to which
              the MySQL server is connected
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        connected_port
       </code>
      </td>
      <td>
       The port used by the MySQL server to connect to the management server
              (
       <code class="literal">
        connected_host
       </code>
       )
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        number_of_data_nodes
       </code>
      </td>
      <td>
       The number of data nodes configured for the cluster (that is, the number
              of
       <code class="literal">
        [ndbd]
       </code>
       sections in the cluster
       <code class="filename">
        config.ini
       </code>
       file)
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        number_of_ready_data_nodes
       </code>
      </td>
      <td>
       The number of data nodes in the cluster that are actually running
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        connect_count
       </code>
      </td>
      <td>
       The number of times this
       <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
        <span class="command">
         <strong>
          mysqld
         </strong>
        </span>
       </a>
       has connected or
              reconnected to cluster data nodes
      </td>
     </tr>
    </tbody>
   </table>
  </div>
  <p>
   The
   <code class="literal">
    binlog
   </code>
   row's
   <code class="literal">
    Status
   </code>
   column contains information relating
        to NDB Cluster Replication. The name-value pairs it contains are
        described in the following table.
  </p>
  <div class="informaltable">
   <table summary="Name and value pairs found in the binlog row Status column in the output of the SHOW ENGINE NDB STATUS statement.">
    <colgroup>
     <col style="width: 40%"/>
     <col style="width: 60%"/>
    </colgroup>
    <thead>
     <tr>
      <th>
       Name
      </th>
      <th>
       Value
      </th>
     </tr>
    </thead>
    <tbody>
     <tr>
      <td>
       <code class="literal">
        latest_epoch
       </code>
      </td>
      <td>
       The most recent epoch most recently run on this MySQL server (that is,
              the sequence number of the most recent transaction run on
              the server)
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        latest_trans_epoch
       </code>
      </td>
      <td>
       The most recent epoch processed by the cluster's data nodes
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        latest_received_binlog_epoch
       </code>
      </td>
      <td>
       The most recent epoch received by the binary log thread
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        latest_handled_binlog_epoch
       </code>
      </td>
      <td>
       The most recent epoch processed by the binary log thread (for writing to
              the binary log)
      </td>
     </tr>
     <tr>
      <td>
       <code class="literal">
        latest_applied_binlog_epoch
       </code>
      </td>
      <td>
       The most recent epoch actually written to the binary log
      </td>
     </tr>
    </tbody>
   </table>
  </div>
  <p>
   See
   <a class="xref" href="mysql-cluster-replication.html" title="25.7 NDB Cluster Replication">
    Section 25.7, “NDB Cluster Replication”
   </a>
   , for more
        information.
  </p>
  <p>
   The remaining rows from the output of
   <code class="literal">
    SHOW ENGINE NDB
        STATUS
   </code>
   which are most likely to prove useful in
        monitoring the cluster are listed here by
   <code class="literal">
    Name
   </code>
   :
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       NdbTransaction
      </code>
      : The number and size of
      <code class="literal">
       NdbTransaction
      </code>
      objects that have been
            created. An
      <code class="literal">
       NdbTransaction
      </code>
      is created
            each time a table schema operation (such as
      <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>
      ) is performed on
            an
      <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
       <code class="literal">
        NDB
       </code>
      </a>
      table.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbOperation
      </code>
      : The number and size of
      <code class="literal">
       NdbOperation
      </code>
      objects that have been
            created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbIndexScanOperation
      </code>
      : The number and
            size of
      <code class="literal">
       NdbIndexScanOperation
      </code>
      objects
            that have been created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbIndexOperation
      </code>
      : The number and size of
      <code class="literal">
       NdbIndexOperation
      </code>
      objects that have been
            created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbRecAttr
      </code>
      : The number and size of
      <code class="literal">
       NdbRecAttr
      </code>
      objects that have been
            created. In general, one of these is created each time a
            data manipulation statement is performed by an SQL node.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbBlob
      </code>
      : The number and size of
      <code class="literal">
       NdbBlob
      </code>
      objects that have been created.
            An
      <code class="literal">
       NdbBlob
      </code>
      is created for each new
            operation involving a
      <a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
       <code class="literal">
        BLOB
       </code>
      </a>
      column in an
      <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
       <code class="literal">
        NDB
       </code>
      </a>
      table.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NdbReceiver
      </code>
      : The number and size of any
      <code class="literal">
       NdbReceiver
      </code>
      object that have been
            created. The number in the
      <code class="literal">
       created
      </code>
      column
            is the same as the number of data nodes in the cluster to
            which the MySQL server has connected.
     </p>
    </li>
   </ul>
  </div>
  <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
   <div class="admon-title">
    Note
   </div>
   <p>
    <code class="literal">
     SHOW ENGINE NDB STATUS
    </code>
    returns an empty
          result if no operations involving
    <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
     <code class="literal">
      NDB
     </code>
    </a>
    tables have been performed
          during the current session by the MySQL client accessing the
          SQL node on which this statement is run.
   </p>
  </div>
 </div>
 <br/>
</div>
