disk,
       in milliseconds
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>sync_time</structfield> <type>double precision</type>
      </para>
      <para>
       Total amount of time that has been spent in the portion of
       processing checkpoints and restartpoints where files are synchronized to
       disk, in milliseconds
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>buffers_written</structfield> <type>bigint</type>
      </para>
      <para>
       Number of shared buffers written during checkpoints and restartpoints
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>slru_written</structfield> <type>bigint</type>
      </para>
      <para>
        Number of SLRU buffers written during checkpoints and restartpoints
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>stats_reset</structfield> <type>timestamp with time zone</type>
      </para>
      <para>
       Time at which these statistics were last reset
      </para></entry>
     </row>
    </tbody>
   </tgroup>
  </table>

  <para>
   Checkpoints may be skipped if the server has been idle since the last one.
   <structfield>num_timed</structfield> and
   <structfield>num_requested</structfield> count both completed and skipped
   checkpoints, while <structfield>num_done</structfield> tracks only
   the completed ones.  Similarly, restartpoints may be skipped
   if the last replayed checkpoint record is already the last restartpoint.
   <structfield>restartpoints_timed</structfield> and
   <structfield>restartpoints_req</structfield> count both completed and
   skipped restartpoints, while <structfield>restartpoints_done</structfield>
   tracks only the completed ones.
  </para>
 </sect2>

 <sect2 id="monitoring-pg-stat-wal-view">
   <title><structname>pg_stat_wal</structname></title>

  <indexterm>
   <primary>pg_stat_wal</primary>
  </indexterm>

  <para>
   The <structname>pg_stat_wal</structname> view will always have a
   single row, containing data about WAL activity of the cluster.
  </para>

  <table id="pg-stat-wal-view" xreflabel="pg_stat_wal">
   <title><structname>pg_stat_wal</structname> View</title>
   <tgroup cols="1">
    <thead>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       Column Type
      </para>
      <para>
       Description
      </para></entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>wal_records</structfield> <type>bigint</type>
      </para>
      <para>
       Total number of WAL records generated
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>wal_fpi</structfield> <type>bigint</type>
      </para>
      <para>
       Total number of WAL full page images generated
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>wal_bytes</structfield> <type>numeric</type>
      </para>
      <para>
       Total amount of WAL generated in bytes
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>wal_buffers_full</structfield> <type>bigint</type>
      </para>
      <para>
       Number of times WAL data was written to disk because WAL buffers became full
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>stats_reset</structfield> <type>timestamp with time zone</type>
      </para>
      <para>
       Time at which these