non-numeric
       values)
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>enumvals</structfield> <type>text[]</type>
      </para>
      <para>
       Allowed values of an enum parameter (null for non-enum
       values)
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>boot_val</structfield> <type>text</type>
      </para>
      <para>
       Parameter value assumed at server startup if the parameter is
       not otherwise set
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>reset_val</structfield> <type>text</type>
      </para>
      <para>
       Value that <link linkend="sql-reset"><command>RESET</command></link> would reset the parameter to
       in the current session
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>sourcefile</structfield> <type>text</type>
      </para>
      <para>
       Configuration file the current value was set in (null for
       values set from sources other than configuration files, or when
       examined by a user who neither is a superuser nor has privileges of
       <literal>pg_read_all_settings</literal>); helpful when using
       <literal>include</literal> directives in configuration files
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>sourceline</structfield> <type>int4</type>
      </para>
      <para>
       Line number within the configuration file the current value was
       set at (null for values set from sources other than configuration files,
       or when examined by a user who neither is a superuser nor has privileges of
       <literal>pg_read_all_settings</literal>).
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>pending_restart</structfield> <type>bool</type>
      </para>
      <para>
       <literal>true</literal> if the value has been changed in the
       configuration file but needs a restart; or <literal>false</literal>
       otherwise.
      </para></entry>
     </row>
    </tbody>
   </tgroup>
  </table>

  <para>
   There are several possible values of <structfield>context</structfield>.
   In order of decreasing difficulty of changing the setting, they are:
  </para>

  <variablelist>
   <varlistentry>
    <!-- PGC_INTERNAL -->
    <term><literal>internal</literal></term>
    <listitem>
     <para>
      These settings cannot be changed directly; they reflect internally
      determined values.  Some of them may be adjustable by rebuilding the
      server with different configuration options, or by changing options
      supplied to <application>initdb</application>.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <!-- PGC_POSTMASTER -->
    <term><literal>postmaster</literal></term>
    <listitem>
     <para>
      These settings can only be applied when the server starts, so any change
      requires restarting the server.  Values for these settings are typically
      stored in the <filename>postgresql.conf</filename> file, or passed on
      the command line when starting the server.  Of course, settings with any
      of the lower <structfield>context</structfield> types can also be
      set at server start time.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <!-- PGC_SIGHUP -->
    <term><literal>sighup</literal></term>
    <listitem>
     <para>
      Changes to these settings can be made in
      <filename>postgresql.conf</filename> without restarting the server.
      Send a <systemitem>SIGHUP</systemitem> signal to the postmaster to
      cause it to re-read <filename>postgresql.conf</filename>