<div id="docs-body">
 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h3 class="title">
      <a name="sys-schema-views">
      </a>
      30.4.3 sys Schema Views
     </h3>
    </div>
   </div>
  </div>
  <div class="toc">
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="sys-host-summary.html">
       30.4.3.1 The host_summary and x$host_summary Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-host-summary-by-file-io.html">
       30.4.3.2 The host_summary_by_file_io and x$host_summary_by_file_io Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-host-summary-by-file-io-type.html">
       30.4.3.3 The host_summary_by_file_io_type and x$host_summary_by_file_io_type
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-host-summary-by-stages.html">
       30.4.3.4 The host_summary_by_stages and x$host_summary_by_stages Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-host-summary-by-statement-latency.html">
       30.4.3.5 The host_summary_by_statement_latency and
          x$host_summary_by_statement_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-host-summary-by-statement-type.html">
       30.4.3.6 The host_summary_by_statement_type and x$host_summary_by_statement_type
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-innodb-buffer-stats-by-schema.html">
       30.4.3.7 The innodb_buffer_stats_by_schema and x$innodb_buffer_stats_by_schema
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-innodb-buffer-stats-by-table.html">
       30.4.3.8 The innodb_buffer_stats_by_table and x$innodb_buffer_stats_by_table
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-innodb-lock-waits.html">
       30.4.3.9 The innodb_lock_waits and x$innodb_lock_waits Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-io-by-thread-by-latency.html">
       30.4.3.10 The io_by_thread_by_latency and x$io_by_thread_by_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-io-global-by-file-by-bytes.html">
       30.4.3.11 The io_global_by_file_by_bytes and x$io_global_by_file_by_bytes Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-io-global-by-file-by-latency.html">
       30.4.3.12 The io_global_by_file_by_latency and x$io_global_by_file_by_latency
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-io-global-by-wait-by-bytes.html">
       30.4.3.13 The io_global_by_wait_by_bytes and x$io_global_by_wait_by_bytes Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-io-global-by-wait-by-latency.html">
       30.4.3.14 The io_global_by_wait_by_latency and x$io_global_by_wait_by_latency
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-latest-file-io.html">
       30.4.3.15 The latest_file_io and x$latest_file_io Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-memory-by-host-by-current-bytes.html">
       30.4.3.16 The memory_by_host_by_current_bytes and
          x$memory_by_host_by_current_bytes Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-memory-by-thread-by-current-bytes.html">
       30.4.3.17 The memory_by_thread_by_current_bytes and
          x$memory_by_thread_by_current_bytes Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-memory-by-user-by-current-bytes.html">
       30.4.3.18 The memory_by_user_by_current_bytes and
          x$memory_by_user_by_current_bytes Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-memory-global-by-current-bytes.html">
       30.4.3.19 The memory_global_by_current_bytes and x$memory_global_by_current_bytes
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-memory-global-total.html">
       30.4.3.20 The memory_global_total and x$memory_global_total Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-metrics.html">
       30.4.3.21 The metrics View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-processlist.html">
       30.4.3.22 The processlist and x$processlist Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-ps-check-lost-instrumentation.html">
       30.4.3.23 The ps_check_lost_instrumentation View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-auto-increment-columns.html">
       30.4.3.24 The schema_auto_increment_columns View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-index-statistics.html">
       30.4.3.25 The schema_index_statistics and x$schema_index_statistics Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-object-overview.html">
       30.4.3.26 The schema_object_overview View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-redundant-indexes.html">
       30.4.3.27 The schema_redundant_indexes and x$schema_flattened_keys Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-table-lock-waits.html">
       30.4.3.28 The schema_table_lock_waits and x$schema_table_lock_waits Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-table-statistics.html">
       30.4.3.29 The schema_table_statistics and x$schema_table_statistics Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-table-statistics-with-buffer.html">
       30.4.3.30 The schema_table_statistics_with_buffer and
          x$schema_table_statistics_with_buffer Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-tables-with-full-table-scans.html">
       30.4.3.31 The schema_tables_with_full_table_scans and
          x$schema_tables_with_full_table_scans Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-schema-unused-indexes.html">
       30.4.3.32 The schema_unused_indexes View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-session.html">
       30.4.3.33 The session and x$session Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-session-ssl-status.html">
       30.4.3.34 The session_ssl_status View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statement-analysis.html">
       30.4.3.35 The statement_analysis and x$statement_analysis Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statements-with-errors-or-warnings.html">
       30.4.3.36 The statements_with_errors_or_warnings and
          x$statements_with_errors_or_warnings Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statements-with-full-table-scans.html">
       30.4.3.37 The statements_with_full_table_scans and
          x$statements_with_full_table_scans Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statements-with-runtimes-in-95th-percentile.html">
       30.4.3.38 The statements_with_runtimes_in_95th_percentile and
          x$statements_with_runtimes_in_95th_percentile Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statements-with-sorting.html">
       30.4.3.39 The statements_with_sorting and x$statements_with_sorting Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-statements-with-temp-tables.html">
       30.4.3.40 The statements_with_temp_tables and x$statements_with_temp_tables Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary.html">
       30.4.3.41 The user_summary and x$user_summary Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary-by-file-io.html">
       30.4.3.42 The user_summary_by_file_io and x$user_summary_by_file_io Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary-by-file-io-type.html">
       30.4.3.43 The user_summary_by_file_io_type and x$user_summary_by_file_io_type
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary-by-stages.html">
       30.4.3.44 The user_summary_by_stages and x$user_summary_by_stages Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary-by-statement-latency.html">
       30.4.3.45 The user_summary_by_statement_latency and
          x$user_summary_by_statement_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-user-summary-by-statement-type.html">
       30.4.3.46 The user_summary_by_statement_type and x$user_summary_by_statement_type
          Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-version.html">
       30.4.3.47 The version View
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-wait-classes-global-by-avg-latency.html">
       30.4.3.48 The wait_classes_global_by_avg_latency and
          x$wait_classes_global_by_avg_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-wait-classes-global-by-latency.html">
       30.4.3.49 The wait_classes_global_by_latency and x$wait_classes_global_by_latency
Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-waits-by-host-by-latency.html">
       30.4.3.50 The waits_by_host_by_latency and x$waits_by_host_by_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-waits-by-user-by-latency.html">
       30.4.3.51 The waits_by_user_by_latency and x$waits_by_user_by_latency Views
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="sys-waits-global-by-latency.html">
       30.4.3.52 The waits_global_by_latency and x$waits_global_by_latency Views
      </a>
     </span>
    </dt>
   </dl>
  </div>
  <p>
   The following sections describe
   <a class="link" href="sys-schema.html" title="Chapter 30 MySQL sys Schema">
    <code class="literal">
     sys
    </code>
   </a>
   schema views.
  </p>
  <a class="indexterm" name="idm46045063392496">
  </a>
  <a class="indexterm" name="idm46045063391008">
  </a>
  <p>
   The
   <code class="literal">
    sys
   </code>
   schema contains many views that
        summarize Performance Schema tables in various ways. Most of
        these views come in pairs, such that one member of the pair has
        the same name as the other member, plus a
   <code class="literal">
    x$
   </code>
   prefix. For example, 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>
   view
        summarizes file I/O grouped by host and displays latencies
        converted from picoseconds to more readable values (with units);
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa52702180"><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">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> sys<span class="token punctuation">.</span>host_summary_by_file_io<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>
<span class="token output"><span class="token punctuation">|</span> host       <span class="token punctuation">|</span> ios   <span class="token punctuation">|</span> io_latency <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>
<span class="token output"><span class="token punctuation">|</span> localhost  <span class="token punctuation">|</span> 67570 <span class="token punctuation">|</span> 5.38 s     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> background <span class="token punctuation">|</span>  3468 <span class="token punctuation">|</span> 4.18 s     <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></code></pre>
  </div>
  <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">
     x$host_summary_by_file_io
    </code>
   </a>
   view
        summarizes the same data but displays unformatted picosecond
        latencies:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa63777722"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> sys<span class="token punctuation">.</span>x$host_summary_by_file_io<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>
<span class="token output"><span class="token punctuation">|</span> host       <span class="token punctuation">|</span> ios   <span class="token punctuation">|</span> io_latency    <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>
<span class="token output"><span class="token punctuation">|</span> localhost  <span class="token punctuation">|</span> 67574 <span class="token punctuation">|</span> 5380678125144 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> background <span class="token punctuation">|</span>  3474 <span class="token punctuation">|</span> 4758696829416 <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></code></pre>
  </div>
  <p>
   The view without the
   <code class="literal">
    x$
   </code>
   prefix is intended to
        provide output that is more user friendly and easier to read.
        The view with the
   <code class="literal">
    x$
   </code>
   prefix that displays the
        same values in raw form is intended more for use with other
        tools that perform their own processing on the data.
  </p>
  <p>
   Views without the
   <code class="literal">
    x$
   </code>
   prefix differ from the
        corresponding
   <code class="literal">
    x$
   </code>
   views in these ways:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Byte counts are formatted with size units using
      <a class="link" href="sys-format-bytes.html" title="30.4.5.3 The format_bytes() Function">
       <code class="literal">
        format_bytes()
       </code>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      Time values are formatted with temporal units using
      <a class="link" href="sys-format-time.html" title="30.4.5.6 The format_time() Function">
       <code class="literal">
        format_time()
       </code>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      SQL statements are truncated to a maximum display width
            using
      <a class="link" href="sys-format-statement.html" title="30.4.5.5 The format_statement() Function">
       <code class="literal">
        format_statement()
       </code>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      Path name are shortened using
      <a class="link" href="sys-format-path.html" title="30.4.5.4 The format_path() Function">
       <code class="literal">
        format_path()
       </code>
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
 </div>
 <br/>
</div>
