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     <h4 class="title">
      <a name="performance-schema-events-waits-history-table">
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      29.12.4.2 The events_waits_history Table
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  <p>
   The
   <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
   <em class="replaceable">
    <code>
     N
    </code>
   </em>
   most recent wait
          events that have ended per thread. Wait events are not added
          to the table until they have ended. When the table contains
          the maximum number of rows for a given thread, the oldest
          thread row is discarded when a new row for that thread is
          added. When a thread ends, all its rows are discarded.
  </p>
  <p>
   The Performance Schema autosizes the value of
   <em class="replaceable">
    <code>
     N
    </code>
   </em>
   during server startup. To set the
          number of rows per thread explicitly, set the
   <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>
   system variable at server startup.
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  <p>
   The
   <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
          has the same columns and indexing as
   <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>
   . See
   <a class="xref" href="performance-schema-events-waits-current-table.html" title="29.12.4.1 The events_waits_current Table">
    Section 29.12.4.1, “The events_waits_current Table”
   </a>
   .
  </p>
  <p>
   <a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
    <code class="literal">
     TRUNCATE TABLE
    </code>
   </a>
   is permitted for
          the
   <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.
          It removes the rows.
  </p>
  <p>
   For more information about the relationship between the three
          wait event tables, see
   <a class="xref" href="performance-schema-event-tables.html" title="29.9 Performance Schema Tables for Current and Historical Events">
    Section 29.9, “Performance Schema Tables for Current and Historical Events”
   </a>
   .
  </p>
  <p>
   For information about configuring whether to collect wait
          events, see
   <a class="xref" href="performance-schema-wait-tables.html" title="29.12.4 Performance Schema Wait Event Tables">
    Section 29.12.4, “Performance Schema Wait Event Tables”
   </a>
   .
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