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     <h4 class="title">
      <a name="sys-host-summary-by-file-io">
      </a>
      30.4.3.2 The host_summary_by_file_io and x$host_summary_by_file_io Views
     </h4>
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  <p>
   These views summarize file I/O, grouped by host. By default,
          rows are sorted by descending total file I/O latency.
  </p>
  <p>
   The
   <a class="link" href="sys-host-summary-by-file-io.html" title="30.4.3.2 The host_summary_by_file_io and x$host_summary_by_file_io Views">
    <code class="literal">
     host_summary_by_file_io
    </code>
   </a>
   and
   <a class="link" href="sys-host-summary-by-file-io.html" title="30.4.3.2 The host_summary_by_file_io and x$host_summary_by_file_io Views">
    <code class="literal">
     x$host_summary_by_file_io
    </code>
   </a>
   views
          have these columns:
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   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       host
      </code>
     </p>
     <p>
      The host from which the client connected. Rows for which
              the
      <code class="literal">
       HOST
      </code>
      column in the underlying
              Performance Schema table is
      <code class="literal">
       NULL
      </code>
      are
              assumed to be for background threads and are reported with
              a host name of
      <code class="literal">
       background
      </code>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       ios
      </code>
     </p>
     <p>
      The total number of file I/O events for the host.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       io_latency
      </code>
     </p>
     <p>
      The total wait time of timed file I/O events for the host.
     </p>
    </li>
   </ul>
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