(<type>boolean</type>)
      <indexterm>
       <primary>bitmap scan</primary>
      </indexterm>
      <indexterm>
       <primary><varname>enable_bitmapscan</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's use of bitmap-scan plan
        types. The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-distinct-reordering" xreflabel="enable_distinct_reordering">
      <term><varname>enable_distinct_reordering</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_distinct_reordering</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's ability to reorder DISTINCT
        keys to match the input path's pathkeys. The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-gathermerge" xreflabel="enable_gathermerge">
      <term><varname>enable_gathermerge</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_gathermerge</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's use of gather
        merge plan types. The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-groupby-reordering" xreflabel="enable_group_by_reordering">
      <term><varname>enable_group_by_reordering</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_group_by_reordering</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Controls if the query planner will produce a plan which will provide
        <literal>GROUP BY</literal> keys sorted in the order of keys of
        a child node of the plan, such as an index scan.  When disabled, the
        query planner will produce a plan with <literal>GROUP BY</literal>
        keys only sorted to match the <literal>ORDER BY</literal> clause,
        if any. When enabled, the planner will try to produce a more
        efficient plan. The default value is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-hashagg" xreflabel="enable_hashagg">
      <term><varname>enable_hashagg</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_hashagg</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's use of hashed
        aggregation plan types. The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-hashjoin" xreflabel="enable_hashjoin">
      <term><varname>enable_hashjoin</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_hashjoin</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's use of hash-join plan
        types. The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-incremental-sort" xreflabel="enable_incremental_sort">
      <term><varname>enable_incremental_sort</varname> (<type>boolean</type>)
      <indexterm>
       <primary><varname>enable_incremental_sort</varname> configuration parameter</primary>
      </indexterm>
      </term>
      <listitem>
       <para>
        Enables or disables the query planner's use of incremental sort steps.
        The default is <literal>on</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="guc-enable-indexscan" xreflabel="enable_indexscan">