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     <h4 class="title">
      <a name="mysql-cluster-ndbinfo-pgman-time-track-stats">
      </a>
      25.6.17.50 The ndbinfo pgman_time_track_stats Table
     </h4>
    </div>
   </div>
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  <a class="indexterm" name="idm46045088278832">
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  <p>
   This table provides information regarding the latency of disk
        operations for NDB Cluster Disk Data tablespaces.
  </p>
  <p>
   The
   <code class="literal">
    pgman_time_track_stats
   </code>
   table contains the
        following columns:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       node_id
      </code>
     </p>
     <p>
      Unique node ID of this node in the cluster
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       block_number
      </code>
     </p>
     <p>
      Block number (from
      <a class="link" href="mysql-cluster-ndbinfo-blocks.html" title="25.6.17.5 The ndbinfo blocks Table">
       <code class="literal">
        blocks
       </code>
      </a>
      table)
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       block_instance
      </code>
     </p>
     <p>
      Block instance number
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       upper_bound
      </code>
     </p>
     <p>
      Upper bound
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       page_reads
      </code>
     </p>
     <p>
      Page read latency (ms)
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       page_writes
      </code>
     </p>
     <p>
      Page write latency (ms)
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       log_waits
      </code>
     </p>
     <p>
      Log wait latency (ms)
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       get_page
      </code>
     </p>
     <p>
      Latency of
      <code class="literal">
       get_page()
      </code>
      calls (ms)
     </p>
    </li>
   </ul>
  </div>
  <h5>
   <a name="idm46045088258064">
   </a>
   Notes
  </h5>
  <p>
   The read latency (
   <code class="literal">
    page_reads
   </code>
   column) measures
        the time from when the read request is sent to the file system
        thread until the read is complete and has been reported back to
        the execution thread. The write latency
        (
   <code class="literal">
    page_writes
   </code>
   ) is calculated in a similar
        fashion. The size of the page read to or written from a Disk
        Data tablespace is always 32 KB.
  </p>
  <p>
   Log wait latency (
   <code class="literal">
    log_waits
   </code>
   column) is the
        length of time a page write must wait for the undo log to be
        flushed, which must be done prior to each page write.
  </p>
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