</indexterm>

<para>

The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command>

The <filename>pg_overexplain</filename>moduleextends <command>EXPLAIN</command>

with new options that provide additional output. It is mostly intended to

assist with debugging of and development of the planner, rather than for

general use. Since this module displays internal details of planner data

often as) those data structures change.

</para>

<para>

To use it, simply load it into the server. You can load it into an

individual session:

<programlisting>

LOAD 'pg_overexplain';

</programlisting>

You can also preload it into some or all sessions by including

<literal>pg_overexplain</literal> in

<xref linkend="guc-session-preload-libraries"/> or

<xref linkend="guc-shared-preload-libraries"/> in

<filename>postgresql.conf</filename>.

</para>

<sect2 id="pgoverexplain-debug">

<title>EXPLAIN (DEBUG)</title>