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 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h3 class="title">
      <a name="information-schema-innodb-buffer-pool-stats-table">
      </a>
      28.4.4 The INFORMATION_SCHEMA INNODB_BUFFER_POOL_STATS Table
     </h3>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045077425312">
  </a>
  <p>
   The
   <a class="link" href="information-schema-innodb-buffer-pool-stats-table.html" title="28.4.4 The INFORMATION_SCHEMA INNODB_BUFFER_POOL_STATS Table">
    <code class="literal">
     INNODB_BUFFER_POOL_STATS
    </code>
   </a>
   table
      provides much of the same buffer pool information provided in
   <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
    <code class="literal">
     SHOW ENGINE INNODB
      STATUS
    </code>
   </a>
   output. Much of the same information may also be
      obtained using
   <code class="literal">
    InnoDB
   </code>
   buffer pool
   <a class="link" href="server-status-variables.html" title="7.1.10 Server Status Variables">
    server status
      variables
   </a>
   .
  </p>
  <p>
   The idea of making pages in the buffer pool
   <span class="quote">
    “
    <span class="quote">
     young
    </span>
    ”
   </span>
   or
   <span class="quote">
    “
    <span class="quote">
     not young
    </span>
    ”
   </span>
   refers to transferring them between
      the
   <a class="link" href="glossary.html#glos_sublist" title="sublist">
    sublists
   </a>
   at the head and
      tail of the buffer pool data structure. Pages made
   <span class="quote">
    “
    <span class="quote">
     young
    </span>
    ”
   </span>
   take longer to age out of the buffer pool,
      while pages made
   <span class="quote">
    “
    <span class="quote">
     not young
    </span>
    ”
   </span>
   are moved much closer to
      the point of
   <a class="link" href="glossary.html#glos_eviction" title="eviction">
    eviction
   </a>
   .
  </p>
  <p>
   For related usage information and examples, see
   <a class="xref" href="innodb-information-schema-buffer-pool-tables.html" title="17.15.5 InnoDB INFORMATION_SCHEMA Buffer Pool Tables">
    Section 17.15.5, “InnoDB INFORMATION_SCHEMA Buffer Pool Tables”
   </a>
   .
  </p>
  <p>
   The
   <a class="link" href="information-schema-innodb-buffer-pool-stats-table.html" title="28.4.4 The INFORMATION_SCHEMA INNODB_BUFFER_POOL_STATS Table">
    <code class="literal">
     INNODB_BUFFER_POOL_STATS
    </code>
   </a>
   table
      has these columns:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       POOL_ID
      </code>
     </p>
     <p>
      The buffer pool ID. This is an identifier to distinguish
          between multiple buffer pool instances.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       POOL_SIZE
      </code>
     </p>
     <p>
      The
      <code class="literal">
       InnoDB
      </code>
      buffer pool size in pages.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       FREE_BUFFERS
      </code>
     </p>
     <p>
      The number of free pages in the
      <code class="literal">
       InnoDB
      </code>
      buffer pool.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       DATABASE_PAGES
      </code>
     </p>
     <p>
      The number of pages in the
      <code class="literal">
       InnoDB
      </code>
      buffer
          pool containing data. This number includes both dirty and
          clean pages.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       OLD_DATABASE_PAGES
      </code>
     </p>
     <p>
      The number of pages in the
      <code class="literal">
       old
      </code>
      buffer pool
          sublist.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       MODIFIED_DATABASE_PAGES
      </code>
     </p>
     <p>
      The number of modified (dirty) database pages.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PENDING_DECOMPRESS
      </code>
     </p>
     <p>
      The number of pages pending decompression.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PENDING_READS
      </code>
     </p>
     <p>
      The number of pending reads.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PENDING_FLUSH_LRU
      </code>
     </p>
     <p>
      The number of pages pending flush in the LRU.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PENDING_FLUSH_LIST
      </code>
     </p>
     <p>
      The number of pages pending flush in the flush list.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_MADE_YOUNG
      </code>
     </p>
     <p>
      The number of pages made young.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_NOT_MADE_YOUNG
      </code>
     </p>
     <p>
      The number of pages not made young.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_MADE_YOUNG_RATE
      </code>
     </p>
     <p>
      The number of pages made young per second (pages made young
          since the last printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_MADE_NOT_YOUNG_RATE
      </code>
     </p>
     <p>
      The number of pages not made per second (pages not made young
          since the last printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_PAGES_READ
      </code>
     </p>
     <p>
      The number of pages read.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_PAGES_CREATED
      </code>
     </p>
     <p>
      The number of pages created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_PAGES_WRITTEN
      </code>
     </p>
     <p>
      The number of pages written.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_READ_RATE
      </code>
     </p>
     <p>
      The number of pages read per second (pages read since the last
          printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_CREATE_RATE
      </code>
     </p>
     <p>
      The number of pages created per second (pages created since
          the last printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PAGES_WRITTEN_RATE
      </code>
     </p>
     <p>
      The number of pages written per second (pages written since
          the last printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_PAGES_GET
      </code>
     </p>
     <p>
      The number of logical read requests.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       HIT_RATE
      </code>
     </p>
     <p>
      The buffer pool hit rate.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       YOUNG_MAKE_PER_THOUSAND_GETS
      </code>
     </p>
     <p>
      The number of pages made young per thousand gets.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NOT_YOUNG_MAKE_PER_THOUSAND_GETS
      </code>
     </p>
     <p>
      The number of pages not made young per thousand gets.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_PAGES_READ_AHEAD
      </code>
     </p>
     <p>
      The number of pages read ahead.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       NUMBER_READ_AHEAD_EVICTED
      </code>
     </p>
     <p>
      The number of pages read into the
      <code class="literal">
       InnoDB
      </code>
      buffer pool by the read-ahead background thread that were
          subsequently evicted without having been accessed by queries.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       READ_AHEAD_RATE
      </code>
     </p>
     <p>
      The read-ahead rate per second (pages read ahead since the
          last printout / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       READ_AHEAD_EVICTED_RATE
      </code>
     </p>
     <p>
      The number of read-ahead pages evicted without access per
          second (read-ahead pages not accessed since the last printout
          / time elapsed).
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       LRU_IO_TOTAL
      </code>
     </p>
     <p>
      Total LRU I/O.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       LRU_IO_CURRENT
      </code>
     </p>
     <p>
      LRU I/O for the current interval.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       UNCOMPRESS_TOTAL
      </code>
     </p>
     <p>
      The total number of pages decompressed.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       UNCOMPRESS_CURRENT
      </code>
     </p>
     <p>
      The number of pages decompressed in the current interval.
     </p>
    </li>
   </ul>
  </div>
  <h4>
   <a name="idm46045077346112">
   </a>
   Example
  </h4>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa75073322"><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> INFORMATION_SCHEMA<span class="token punctuation">.</span>INNODB_BUFFER_POOL_STATS\G
<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> 1. row <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>
                         POOL_ID<span class="token punctuation">:</span> 0
                       POOL_SIZE<span class="token punctuation">:</span> 8192
                    FREE_BUFFERS<span class="token punctuation">:</span> 1
                  DATABASE_PAGES<span class="token punctuation">:</span> 8085
              OLD_DATABASE_PAGES<span class="token punctuation">:</span> 2964
         MODIFIED_DATABASE_PAGES<span class="token punctuation">:</span> 0
              PENDING_DECOMPRESS<span class="token punctuation">:</span> 0
                   PENDING_READS<span class="token punctuation">:</span> 0
               PENDING_FLUSH_LRU<span class="token punctuation">:</span> 0
              PENDING_FLUSH_LIST<span class="token punctuation">:</span> 0
                PAGES_MADE_YOUNG<span class="token punctuation">:</span> 22821
            PAGES_NOT_MADE_YOUNG<span class="token punctuation">:</span> 3544303
           PAGES_MADE_YOUNG_RATE<span class="token punctuation">:</span> 357.62602199870594
       PAGES_MADE_NOT_YOUNG_RATE<span class="token punctuation">:</span> 0
               NUMBER_PAGES_READ<span class="token punctuation">:</span> 2389
            NUMBER_PAGES_CREATED<span class="token punctuation">:</span> 12385
            NUMBER_PAGES_WRITTEN<span class="token punctuation">:</span> 13111
                 PAGES_READ_RATE<span class="token punctuation">:</span> 0
               PAGES_CREATE_RATE<span class="token punctuation">:</span> 0
              PAGES_WRITTEN_RATE<span class="token punctuation">:</span> 0
                NUMBER_PAGES_GET<span class="token punctuation">:</span> 33322210
                        HIT_RATE<span class="token punctuation">:</span> 1000
    YOUNG_MAKE_PER_THOUSAND_GETS<span class="token punctuation">:</span> 18
NOT_YOUNG_MAKE_PER_THOUSAND_GETS<span class="token punctuation">:</span> 0
         NUMBER_PAGES_READ_AHEAD<span class="token punctuation">:</span> 2024
       NUMBER_READ_AHEAD_EVICTED<span class="token punctuation">:</span> 0
                 READ_AHEAD_RATE<span class="token punctuation">:</span> 0
         READ_AHEAD_EVICTED_RATE<span class="token punctuation">:</span> 0
                    LRU_IO_TOTAL<span class="token punctuation">:</span> 0
                  LRU_IO_CURRENT<span class="token punctuation">:</span> 0
                UNCOMPRESS_TOTAL<span class="token punctuation">:</span> 0
              UNCOMPRESS_CURRENT<span class="token punctuation">:</span> 0</span></code></pre>
  </div>
  <h4>
   <a name="idm46045077341184">
   </a>
   Notes
  </h4>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      This table is useful primarily for expert-level performance
          monitoring, or when developing performance-related extensions
          for MySQL.
     </p>
    </li>
    <li class="listitem">
     <p>
      You must have the
      <a class="link" href="privileges-provided.html#priv_process">
       <code class="literal">
        PROCESS
       </code>
      </a>
      privilege to query this table.
     </p>
    </li>
    <li class="listitem">
     <p>
      Use the
      <code class="literal">
       INFORMATION_SCHEMA
      </code>
      <a class="link" href="information-schema-columns-table.html" title="28.3.8 The INFORMATION_SCHEMA COLUMNS Table">
       <code class="literal">
        COLUMNS
       </code>
      </a>
      table or the
      <a class="link" href="show-columns.html" title="15.7.7.6 SHOW COLUMNS Statement">
       <code class="literal">
        SHOW COLUMNS
       </code>
      </a>
      statement to view
          additional information about the columns of this table,
          including data types and default values.
     </p>
    </li>
   </ul>
  </div>
 </div>
 <br/>
</div>
