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  <div class="titlepage">
   <div>
    <div>
     <h2 class="title">
      <a name="performance-schema-table-descriptions">
      </a>
      29.12 Performance Schema Table Descriptions
     </h2>
    </div>
   </div>
  </div>
  <div class="toc">
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="performance-schema-table-reference.html">
       29.12.1 Performance Schema Table Reference
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-setup-tables.html">
       29.12.2 Performance Schema Setup Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-instance-tables.html">
       29.12.3 Performance Schema Instance Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-wait-tables.html">
       29.12.4 Performance Schema Wait Event Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-stage-tables.html">
       29.12.5 Performance Schema Stage Event Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-statement-tables.html">
       29.12.6 Performance Schema Statement Event Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-transaction-tables.html">
       29.12.7 Performance Schema Transaction Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-connection-tables.html">
       29.12.8 Performance Schema Connection Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-connection-attribute-tables.html">
       29.12.9 Performance Schema Connection Attribute Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-user-variable-tables.html">
       29.12.10 Performance Schema User-Defined Variable Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-replication-tables.html">
       29.12.11 Performance Schema Replication Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-ndb-cluster-tables.html">
       29.12.12 Performance Schema NDB Cluster Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-lock-tables.html">
       29.12.13 Performance Schema Lock Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-system-variable-tables.html">
       29.12.14 Performance Schema System Variable Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-status-variable-tables.html">
       29.12.15 Performance Schema Status Variable Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-thread-pool-tables.html">
       29.12.16 Performance Schema Thread Pool Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-firewall-tables.html">
       29.12.17 Performance Schema Firewall Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-keyring-tables.html">
       29.12.18 Performance Schema Keyring Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-clone-tables.html">
       29.12.19 Performance Schema Clone Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-summary-tables.html">
       29.12.20 Performance Schema Summary Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-telemetry-tables.html">
       29.12.21 Performance Schema Telemetry Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="performance-schema-miscellaneous-tables.html">
       29.12.22 Performance Schema Miscellaneous Tables
      </a>
     </span>
    </dt>
   </dl>
  </div>
  <p>
   Tables in the
   <code class="literal">
    performance_schema
   </code>
   database can
      be grouped as follows:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Setup tables. These tables are used to configure and display
          monitoring characteristics.
     </p>
    </li>
    <li class="listitem">
     <p>
      Current events tables. The
      <a class="link" href="performance-schema-events-waits-current-table.html" title="29.12.4.1 The events_waits_current Table">
       <code class="literal">
        events_waits_current
       </code>
      </a>
      table
          contains the most recent event for each thread. Other similar
          tables contain current events at different levels of the event
          hierarchy:
      <a class="link" href="performance-schema-events-stages-current-table.html" title="29.12.5.1 The events_stages_current Table">
       <code class="literal">
        events_stages_current
       </code>
      </a>
      for stage events,
      <a class="link" href="performance-schema-events-statements-current-table.html" title="29.12.6.1 The events_statements_current Table">
       <code class="literal">
        events_statements_current
       </code>
      </a>
      for
          statement events, and
      <a class="link" href="performance-schema-events-transactions-current-table.html" title="29.12.7.1 The events_transactions_current Table">
       <code class="literal">
        events_transactions_current
       </code>
      </a>
      for
          transaction events.
     </p>
    </li>
    <li class="listitem">
     <p>
      History tables. These tables have the same structure as the
          current events tables, but contain more rows. For example, for
          wait events,
      <a class="link" href="performance-schema-events-waits-history-table.html" title="29.12.4.2 The events_waits_history Table">
       <code class="literal">
        events_waits_history
       </code>
      </a>
      table contains the most recent 10 events per thread.
      <a class="link" href="performance-schema-events-waits-history-long-table.html" title="29.12.4.3 The events_waits_history_long Table">
       <code class="literal">
        events_waits_history_long
       </code>
      </a>
      contains the most recent 10,000 events. Other similar tables
          exist for stage, statement, and transaction histories.
     </p>
     <p>
      To change the sizes of the history tables, set the appropriate
          system variables at server startup. For example, to set the
          sizes of the wait event history tables, set
      <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>
      and
      <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>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      Summary tables. These tables contain information aggregated
          over groups of events, including those that have been
          discarded from the history tables.
     </p>
    </li>
    <li class="listitem">
     <p>
      Instance tables. These tables document what types of objects
          are instrumented. An instrumented object, when used by the
          server, produces an event. These tables provide event names
          and explanatory notes or status information.
     </p>
    </li>
    <li class="listitem">
     <p>
      Miscellaneous tables. These do not fall into any of the other
          table groups.
     </p>
    </li>
   </ul>
  </div>
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