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 <div class="section">
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    <div>
     <h2 class="title">
      <a name="performance-schema-status-variables">
      </a>
      29.16 Performance Schema Status Variables
     </h2>
    </div>
   </div>
  </div>
  <p>
   The Performance Schema implements several status variables that
      provide information about instrumentation that could not be loaded
      or created due to memory constraints:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa8824589"><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">SHOW</span> <span class="token keyword">STATUS</span> <span class="token operator">LIKE</span> <span class="token string">'perf%'</span><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 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> Variable_name                                         <span class="token punctuation">|</span> Value <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 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> Performance_schema_accounts_lost                      <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_cond_classes_lost                  <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_cond_instances_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_digest_lost                        <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_file_classes_lost                  <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_file_handles_lost                  <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_file_instances_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_hosts_lost                         <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_index_stat_lost                    <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_locker_lost                        <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_memory_classes_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_metadata_lock_lost                 <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_meter_lost                         <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_metric_lost                        <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_mutex_classes_lost                 <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_mutex_instances_lost               <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_nested_statement_lost              <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_prepared_statements_lost           <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_program_lost                       <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_rwlock_classes_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_rwlock_instances_lost              <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_session_connect_attrs_longest_seen <span class="token punctuation">|</span> 131   <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_session_connect_attrs_lost         <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_socket_classes_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_socket_instances_lost              <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_stage_classes_lost                 <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_statement_classes_lost             <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_table_handles_lost                 <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_table_instances_lost               <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_table_lock_stat_lost               <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_thread_classes_lost                <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_thread_instances_lost              <span class="token punctuation">|</span> 0     <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Performance_schema_users_lost                         <span class="token punctuation">|</span> 0     <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 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>
   For information on using these variables to check Performance
      Schema status, see
   <a class="xref" href="performance-schema-status-monitoring.html" title="29.7 Performance Schema Status Monitoring">
    Section 29.7, “Performance Schema Status Monitoring”
   </a>
   .
  </p>
  <p>
   Performance Schema status variables have the following meanings:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_accounts_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_accounts_lost">
       <code class="literal">
        Performance_schema_accounts_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064534336">
     </a>
     <a class="indexterm" name="idm46045064533296">
     </a>
     <p>
      The number of times a row could not be added to the
      <a class="link" href="performance-schema-accounts-table.html" title="29.12.8.1 The accounts Table">
       <code class="literal">
        accounts
       </code>
      </a>
      table because it was
          full.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_cond_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_cond_classes_lost">
       <code class="literal">
        Performance_schema_cond_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064527472">
     </a>
     <a class="indexterm" name="idm46045064526432">
     </a>
     <p>
      How many condition instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_cond_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_cond_instances_lost">
       <code class="literal">
        Performance_schema_cond_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064521920">
     </a>
     <a class="indexterm" name="idm46045064520880">
     </a>
     <p>
      How many condition instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_digest_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_digest_lost">
       <code class="literal">
        Performance_schema_digest_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064516416">
     </a>
     <a class="indexterm" name="idm46045064515312">
     </a>
     <p>
      The number of digest instances that could not be instrumented
          in the
      <a class="link" href="performance-schema-statement-summary-tables.html" title="29.12.20.3 Statement Summary Tables">
       <code class="literal">
        events_statements_summary_by_digest
       </code>
      </a>
      table. This can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_digests_size">
       <code class="literal">
        performance_schema_digests_size
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_file_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_file_classes_lost">
       <code class="literal">
        Performance_schema_file_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064508112">
     </a>
     <a class="indexterm" name="idm46045064507072">
     </a>
     <p>
      How many file instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_file_handles_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_file_handles_lost">
       <code class="literal">
        Performance_schema_file_handles_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064502496">
     </a>
     <a class="indexterm" name="idm46045064501456">
     </a>
     <p>
      How many file instrument instances could not be opened.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_file_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_file_instances_lost">
       <code class="literal">
        Performance_schema_file_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064496928">
     </a>
     <a class="indexterm" name="idm46045064495888">
     </a>
     <p>
      How many file instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_hosts_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_hosts_lost">
       <code class="literal">
        Performance_schema_hosts_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064491488">
     </a>
     <a class="indexterm" name="idm46045064490384">
     </a>
     <p>
      The number of times a row could not be added to the
      <a class="link" href="performance-schema-hosts-table.html" title="29.12.8.2 The hosts Table">
       <code class="literal">
        hosts
       </code>
      </a>
      table because it was full.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_index_stat_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_index_stat_lost">
       <code class="literal">
        Performance_schema_index_stat_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064484576">
     </a>
     <a class="indexterm" name="idm46045064483536">
     </a>
     <p>
      The number of indexes for which statistics were lost. This can
          be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_index_stat">
       <code class="literal">
        performance_schema_max_index_stat
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_locker_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_locker_lost">
       <code class="literal">
        Performance_schema_locker_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064477696">
     </a>
     <a class="indexterm" name="idm46045064476592">
     </a>
     <p>
      How many events are
      <span class="quote">
       “
       <span class="quote">
        lost
       </span>
       ”
      </span>
      or not recorded, due
          to the following conditions:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         Events are recursive (for example, waiting for A caused a
              wait on B, which caused a wait on C).
        </p>
       </li>
       <li class="listitem">
        <p>
         The depth of the nested events stack is greater than the
              limit imposed by the implementation.
        </p>
       </li>
      </ul>
     </div>
     <p>
      Events recorded by the Performance Schema are not recursive,
          so this variable should always be 0.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_memory_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_memory_classes_lost">
       <code class="literal">
        Performance_schema_memory_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064468864">
     </a>
     <a class="indexterm" name="idm46045064467824">
     </a>
     <p>
      The number of times a memory instrument could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_metadata_lock_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_metadata_lock_lost">
       <code class="literal">
        Performance_schema_metadata_lock_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064463232">
     </a>
     <a class="indexterm" name="idm46045064462192">
     </a>
     <p>
      The number of metadata locks that could not be instrumented in
          the
      <a class="link" href="performance-schema-metadata-locks-table.html" title="29.12.13.3 The metadata_locks Table">
       <code class="literal">
        metadata_locks
       </code>
      </a>
      table. This
          can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_metadata_locks">
       <code class="literal">
        performance_schema_max_metadata_locks
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_meter_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_meter_lost">
       <code class="literal">
        Performance_schema_meter_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064455136">
     </a>
     <a class="indexterm" name="idm46045064454032">
     </a>
     <p>
      Number of meter instruments that failed to be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_metric_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_metric_lost">
       <code class="literal">
        Performance_schema_metric_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064449568">
     </a>
     <a class="indexterm" name="idm46045064448464">
     </a>
     <p>
      Number of metric instruments that failed to be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_mutex_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_mutex_classes_lost">
       <code class="literal">
        Performance_schema_mutex_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064443872">
     </a>
     <a class="indexterm" name="idm46045064442832">
     </a>
     <p>
      How many mutex instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_mutex_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_mutex_instances_lost">
       <code class="literal">
        Performance_schema_mutex_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064438256">
     </a>
     <a class="indexterm" name="idm46045064437216">
     </a>
     <p>
      How many mutex instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_nested_statement_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_nested_statement_lost">
       <code class="literal">
        Performance_schema_nested_statement_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064432672">
     </a>
     <a class="indexterm" name="idm46045064431552">
     </a>
     <p>
      The number of stored program statements for which statistics
          were lost. This can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_statement_stack">
       <code class="literal">
        performance_schema_max_statement_stack
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_prepared_statements_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_prepared_statements_lost">
       <code class="literal">
        Performance_schema_prepared_statements_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064425600">
     </a>
     <a class="indexterm" name="idm46045064424480">
     </a>
     <p>
      The number of prepared statements that could not be
          instrumented in the
      <a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
       <code class="literal">
        prepared_statements_instances
       </code>
      </a>
      table. This can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_prepared_statements_instances">
       <code class="literal">
        performance_schema_max_prepared_statements_instances
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_program_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_program_lost">
       <code class="literal">
        Performance_schema_program_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064417232">
     </a>
     <a class="indexterm" name="idm46045064416128">
     </a>
     <p>
      The number of stored programs for which statistics were lost.
          This can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_program_instances">
       <code class="literal">
        performance_schema_max_program_instances
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_rwlock_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_rwlock_classes_lost">
       <code class="literal">
        Performance_schema_rwlock_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064410208">
     </a>
     <a class="indexterm" name="idm46045064409168">
     </a>
     <p>
      How many rwlock instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_rwlock_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_rwlock_instances_lost">
       <code class="literal">
        Performance_schema_rwlock_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064404720">
     </a>
     <a class="indexterm" name="idm46045064403600">
     </a>
     <p>
      How many rwlock instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_session_connect_attrs_longest_seen">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_session_connect_attrs_longest_seen">
       <code class="literal">
        Performance_schema_session_connect_attrs_longest_seen
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064398960">
     </a>
     <a class="indexterm" name="idm46045064397920">
     </a>
     <p>
      In addition to the connection attribute size-limit check
          performed by the Performance Schema against the value of the
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_session_connect_attrs_size">
       <code class="literal">
        performance_schema_session_connect_attrs_size
       </code>
      </a>
      system variable, the server performs a preliminary check,
          imposing a limit of 64KB on the aggregate size of connection
          attribute data it accepts. If a client attempts to send more
          than 64KB of attribute data, the server rejects the
          connection. Otherwise, the server considers the attribute
          buffer valid and tracks the size of the longest such buffer in
          the
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_session_connect_attrs_longest_seen">
       <code class="literal">
        Performance_schema_session_connect_attrs_longest_seen
       </code>
      </a>
      status variable. If this value is larger than
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_session_connect_attrs_size">
       <code class="literal">
        performance_schema_session_connect_attrs_size
       </code>
      </a>
      ,
          DBAs may wish to increase the latter value, or, alternatively,
          investigate which clients are sending large amounts of
          attribute data.
     </p>
     <p>
      For more information about connection attributes, see
      <a class="xref" href="performance-schema-connection-attribute-tables.html" title="29.12.9 Performance Schema Connection Attribute Tables">
       Section 29.12.9, “Performance Schema Connection Attribute Tables”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_session_connect_attrs_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_session_connect_attrs_lost">
       <code class="literal">
        Performance_schema_session_connect_attrs_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064387504">
     </a>
     <a class="indexterm" name="idm46045064386384">
     </a>
     <p>
      The number of connections for which connection attribute
          truncation has occurred. For a given connection, if the client
          sends connection attribute key-value pairs for which the
          aggregate size is larger than the reserved storage permitted
          by the value of the
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_session_connect_attrs_size">
       <code class="literal">
        performance_schema_session_connect_attrs_size
       </code>
      </a>
      system variable, the Performance Schema truncates the
          attribute data and increments
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_session_connect_attrs_lost">
       <code class="literal">
        Performance_schema_session_connect_attrs_lost
       </code>
      </a>
      .
          If this value is nonzero, you may wish to set
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_session_connect_attrs_size">
       <code class="literal">
        performance_schema_session_connect_attrs_size
       </code>
      </a>
      to a larger value.
     </p>
     <p>
      For more information about connection attributes, see
      <a class="xref" href="performance-schema-connection-attribute-tables.html" title="29.12.9 Performance Schema Connection Attribute Tables">
       Section 29.12.9, “Performance Schema Connection Attribute Tables”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_socket_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_socket_classes_lost">
       <code class="literal">
        Performance_schema_socket_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064376240">
     </a>
     <a class="indexterm" name="idm46045064375200">
     </a>
     <p>
      How many socket instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_socket_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_socket_instances_lost">
       <code class="literal">
        Performance_schema_socket_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064370672">
     </a>
     <a class="indexterm" name="idm46045064369552">
     </a>
     <p>
      How many socket instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_stage_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_stage_classes_lost">
       <code class="literal">
        Performance_schema_stage_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064365008">
     </a>
     <a class="indexterm" name="idm46045064363968">
     </a>
     <p>
      How many stage instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_statement_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_statement_classes_lost">
       <code class="literal">
        Performance_schema_statement_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064359504">
     </a>
     <a class="indexterm" name="idm46045064358384">
     </a>
     <p>
      How many statement instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_table_handles_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_table_handles_lost">
       <code class="literal">
        Performance_schema_table_handles_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064353856">
     </a>
     <a class="indexterm" name="idm46045064352816">
     </a>
     <p>
      How many table instrument instances could not be opened. This
          can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_table_handles">
       <code class="literal">
        performance_schema_max_table_handles
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_table_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_table_instances_lost">
       <code class="literal">
        Performance_schema_table_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064346848">
     </a>
     <a class="indexterm" name="idm46045064345808">
     </a>
     <p>
      How many table instrument instances could not be created.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_table_lock_stat_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_table_lock_stat_lost">
       <code class="literal">
        Performance_schema_table_lock_stat_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064341216">
     </a>
     <a class="indexterm" name="idm46045064340176">
     </a>
     <p>
      The number of tables for which lock statistics were lost. This
          can be nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_table_lock_stat">
       <code class="literal">
        performance_schema_max_table_lock_stat
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_thread_classes_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_thread_classes_lost">
       <code class="literal">
        Performance_schema_thread_classes_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064334208">
     </a>
     <a class="indexterm" name="idm46045064333168">
     </a>
     <p>
      How many thread instruments could not be loaded.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_thread_instances_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_thread_instances_lost">
       <code class="literal">
        Performance_schema_thread_instances_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064328704">
     </a>
     <a class="indexterm" name="idm46045064327584">
     </a>
     <p>
      The number of thread instances that could not be instrumented
          in the
      <a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
       <code class="literal">
        threads
       </code>
      </a>
      table. This can be
          nonzero if the value of
      <a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_thread_instances">
       <code class="literal">
        performance_schema_max_thread_instances
       </code>
      </a>
      is too small.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a name="statvar_Performance_schema_users_lost">
      </a>
      <a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_users_lost">
       <code class="literal">
        Performance_schema_users_lost
       </code>
      </a>
     </p>
     <a class="indexterm" name="idm46045064320448">
     </a>
     <a class="indexterm" name="idm46045064319344">
     </a>
     <p>
      The number of times a row could not be added to the
      <a class="link" href="performance-schema-users-table.html" title="29.12.8.3 The users Table">
       <code class="literal">
        users
       </code>
      </a>
      table because it was full.
     </p>
    </li>
   </ul>
  </div>
 </div>
 <br/>
</div>
