of <structfield>enumsortorder</structfield>.
   The only requirement on these values is that they be correctly
   ordered and unique within each enum type.
  </para>
 </sect1>


 <sect1 id="catalog-pg-event-trigger">
  <title><structname>pg_event_trigger</structname></title>

  <indexterm zone="catalog-pg-event-trigger">
   <primary>pg_event_trigger</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_event_trigger</structname> stores event triggers.
   See <xref linkend="event-triggers"/> for more information.
  </para>

  <table>
   <title><structname>pg_event_trigger</structname> Columns</title>
   <tgroup cols="1">
    <thead>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       Column Type
      </para>
      <para>
       Description
      </para></entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>oid</structfield> <type>oid</type>
      </para>
      <para>
       Row identifier
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evtname</structfield> <type>name</type>
      </para>
      <para>
       Trigger name (must be unique)
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evtevent</structfield> <type>name</type>
      </para>
      <para>
       Identifies the event for which this trigger fires
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evtowner</structfield> <type>oid</type>
       (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       Owner of the event trigger
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evtfoid</structfield> <type>oid</type>
       (references <link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       The function to be called
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evtenabled</structfield> <type>char</type>
      </para>
      <para>
       Controls in which <xref linkend="guc-session-replication-role"/> modes
       the event trigger fires.
       <literal>O</literal> = trigger fires in <quote>origin</quote> and <quote>local</quote> modes,
       <literal>D</literal> = trigger is disabled,
       <literal>R</literal> = trigger fires in <quote>replica</quote> mode,
       <literal>A</literal> = trigger fires always.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>evttags</structfield> <type>text[]</type>
      </para>
      <para>
       Command tags for which this trigger will fire.  If NULL, the firing
       of this trigger is not restricted on the basis of the command tag.
      </para></entry>
     </row>
    </tbody>
   </tgroup>
  </table>
 </sect1>


 <sect1 id="catalog-pg-extension">
  <title><structname>pg_extension</structname></title>

  <indexterm zone="catalog-pg-extension">
   <primary>pg_extension</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_extension</structname> stores information
   about the installed extensions.  See <xref linkend="extend-extensions"/>
   for details about extensions.
  </para>

  <table>
   <title><structname>pg_extension</structname> Columns</title>
   <tgroup cols="1">
    <thead>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       Column Type
      </para>
      <para>
       Description
      </para></entry>
     </row>
    </thead>