doc/src/sgml/ref/alter_statistics.sgml - master - githubmirror/postgres

doc/src/sgml/ref/alter_statistics.sgml
137 строк4 KB
Peter Eisentraut
Make stxstattarget nullable
17 мар 2024, 14:26
17 мар 2024, 14:26012460e
<!--
doc/src/sgml/ref/alter_statistics.sgml
PostgreSQL documentation
-->

<refentry id="sql-alterstatistics">
 <indexterm zone="sql-alterstatistics">
  <primary>ALTER STATISTICS</primary>
 </indexterm>

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

 <refnamediv>
  <refname>ALTER STATISTICS</refname>
  <refpurpose>
   change the definition of an extended statistics object
  </refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER STATISTICS <replaceable class="parameter">name</replaceable> OWNER TO { <replaceable class="parameter">new_owner</replaceable> | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
ALTER STATISTICS <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER STATISTICS <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
ALTER STATISTICS <replaceable class="parameter">name</replaceable> SET STATISTICS { <replaceable class="parameter">new_target</replaceable> | DEFAULT }
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER STATISTICS</command> changes the parameters of an existing
   extended statistics object.  Any parameters not specifically set in the
   <command>ALTER STATISTICS</command> command retain their prior settings.
  </para>

  <para>
   You must own the statistics object to use <command>ALTER STATISTICS</command>.
   To change a statistics object's schema, you must also
   have <literal>CREATE</literal> privilege on the new schema.
   To alter the owner, you must be able to <literal>SET ROLE</literal> to the
   new owning role, and that role must have <literal>CREATE</literal>
   privilege on the statistics object's schema.
   (These restrictions enforce that altering
   the owner doesn't do anything you couldn't do by dropping and recreating
   the statistics object.  However, a superuser can alter ownership of any
   statistics object anyway.)
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

   <para>
    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">name</replaceable></term>
      <listitem>
       <para>
        The name (optionally schema-qualified) of the statistics object to be
        altered.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="parameter">new_owner</replaceable></term>
      <listitem>
       <para>
        The user name of the new owner of the statistics object.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="parameter">new_name</replaceable></term>
      <listitem>
       <para>
        The new name for the statistics object.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="parameter">new_schema</replaceable></term>
      <listitem>
       <para>
        The new schema for the statistics object.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="parameter">new_target</replaceable></term>
      <listitem>
       <para>
        The statistic-gathering target for this statistics object for subsequent
        <link linkend="sql-analyze"><command>ANALYZE</command></link> operations.
        The target can be set in the range 0 to 10000.  Set it to
        <literal>DEFAULT</literal> to revert to using the system default
        statistics target (<xref linkend="guc-default-statistics-target"/>).
        (Setting to a value of -1 is an obsolete way spelling to get the same
        outcome.)
        For more information on the use of statistics by the
        <productname>PostgreSQL</productname> query planner, refer to
        <xref linkend="planner-stats"/>.
       </para>
      </listitem>
     </varlistentry>

    </variablelist>
   </para>
  </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   There is no <command>ALTER STATISTICS</command> command in the SQL standard.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createstatistics"/></member>
   <member><xref linkend="sql-dropstatistics"/></member>
  </simplelist>
 </refsect1>

</refentry>