Document pgFouine and check_postgres as log analysis options.

doc/src/sgml/maintenance.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.103 2010/04/16 02:22:33 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.104 2010/05/26 23:29:45 momjian Exp $ -->
 
 <chapter id="maintenance">
  <title>Routine Database Maintenance Tasks</title>
@@ -821,5 +821,14 @@ pg_ctl start | rotatelogs /var/log/pgsql_log 86400
    is to configure the rotation program so that old log files are overwritten
    cyclically.
   </para>
+
+  <para>
+   <ulink url="http://pgfouine.projects.postgresql.org/">pgFouine</ulink>
+   is an external project that does sophisticated log file analysis.
+   <ulink
+   href="http://bucardo.org/wiki/Check_postgres">check_postgres</ulink>
+   provides Nagios alerts when important messages appear in the log
+   files, as well as detection of many other extraordinary conditions.
+  </para>
  </sect1>
 </chapter>