<!--
doc/src/sgml/ref/analyze.sgml
PostgreSQL documentation
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<refentry id="sql-analyze">
 <indexterm zone="sql-analyze">
  <primary>ANALYZE</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ANALYZE</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ANALYZE</refname>
  <refpurpose>collect statistics about a database</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ANALYZE [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <replaceable class="parameter">table_and_columns</replaceable> [, ...] ]

<phrase>where <replaceable class="parameter">option</replaceable> can be one of:</phrase>

    VERBOSE [ <replaceable class="parameter">boolean</replaceable> ]
    SKIP_LOCKED [ <replaceable class="parameter">boolean</replaceable> ]
    BUFFER_USAGE_LIMIT <replaceable class="parameter">size</replaceable>

<phrase>and <replaceable class="parameter">table_and_columns</replaceable> is:</phrase>

    [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ] [ ( <replaceable class="parameter">column_name</replaceable> [, ...] ) ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ANALYZE</command> collects statistics about the contents
   of tables in the database, and stores the results in the <link
   linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>
   system catalog.  Subsequently, the query planner uses these
   statistics to help determine the most efficient execution plans for
   queries.
  </para>

  <para>
   Without a <replaceable class="parameter">table_and_columns</replaceable>
   list, <command>ANALYZE</command> processes every table and materialized view
   in the current database that the current user has permission to analyze.
   With a list, <command>ANALYZE</command> processes only those table(s).
   It is further possible to give a list of column names for a table,
   in which case only the statistics for those columns are collected.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><literal>VERBOSE</literal></term>
    <listitem>
     <para>
      Enables display of progress messages at <literal>INFO</literal> level.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>SKIP_LOCKED</literal></term>
    <listitem>
     <para>
      Specifies that <command>ANALYZE</command> should not wait for any
      conflicting locks to be released when beginning work on a relation:
      if a relation cannot be locked immediately without waiting, the relation
      is skipped.  Note that even with this option, <command>ANALYZE</command>
      may still block when opening the relation's indexes or when acquiring
      sample rows from partitions, table inheritance children, and some
      types of foreign tables.  Also, while <command>ANALYZE</command>
      ordinarily processes all partitions of specified partitioned tables,
      this option will cause <command>ANALYZE</command> to skip all
      partitions if there is a conflicting lock on the partitioned table.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>BUFFER_USAGE_LIMIT</literal></term>
    <listitem>
     <para>
      Specifies the
      <glossterm linkend="glossary-buffer-access-strategy">Buffer Access Strategy</glossterm>
      ring buffer size for <command>ANALYZE</command>.  This size is used to
      calculate the number of shared buffers which will be reused as part of
      this strategy.  <literal>0</literal> disables use of a
      <literal>Buffer Access Strategy</literal>.   When this option is not
      specified, <command>ANALYZE</command> uses the value from
      <xref linkend="guc-vacuum-buffer-usage-limit"/>.  Higher settings can
      allow <command>ANALYZE</command> to run more quickly, but having too
      large a setting may cause