writes) from operating on the
   table until the <command>CLUSTER</command> is finished.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">table_name</replaceable></term>
    <listitem>
     <para>
      The name (possibly schema-qualified) of a table.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">index_name</replaceable></term>
    <listitem>
     <para>
      The name of an index.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>VERBOSE</literal></term>
    <listitem>
     <para>
      Prints a progress report as each table is clustered
      at <literal>INFO</literal> level.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">boolean</replaceable></term>
    <listitem>
     <para>
      Specifies whether the selected option should be turned on or off.
      You can write <literal>TRUE</literal>, <literal>ON</literal>, or
      <literal>1</literal> to enable the option, and <literal>FALSE</literal>,
      <literal>OFF</literal>, or <literal>0</literal> to disable it.  The
      <replaceable class="parameter">boolean</replaceable> value can also
      be omitted, in which case <literal>TRUE</literal> is assumed.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

   <para>
    To cluster a table, one must have the <literal>MAINTAIN</literal> privilege
    on the table.
   </para>

   <para>
    In cases where you are accessing single rows randomly
    within a table, the actual order of the data in the
    table is unimportant. However, if you tend to access some
    data more than others, and there is an index that groups
    them together, you will benefit from using <command>CLUSTER</command>.
    If you are requesting a range of indexed values from a table, or a
    single indexed value that has multiple rows that match,
    <command>CLUSTER</command> will help because once the index identifies the
    table page for the first row that matches, all other rows
    that match are probably already on the same table page,
    and so you save disk accesses and speed up the query.
   </para>

   <para>
    <command>CLUSTER</command> can re-sort the table using either an index scan
    on the specified index, or (if the index is a b-tree) a sequential
    scan followed by sorting.  It will attempt to choose the method that
    will be faster, based on planner cost parameters and available statistical
    information.
   </para>

   <para>
    While <command>CLUSTER</command> is running, the <xref
    linkend="guc-search-path"/> is temporarily changed to <literal>pg_catalog,
    pg_temp</literal>.
   </para>

   <para>
    When an index scan is used, a temporary copy of the table is created that
    contains the table data in the index order.  Temporary copies of each
    index on the table are created as well.  Therefore, you need free space on
    disk at least equal to the sum of the table size and the index sizes.
   </para>

   <para>
    When a sequential scan and sort is used, a temporary sort file is
    also created, so that the peak