-<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.76 2007/07/18 03:39:01 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.77 2007/07/23 17:22:00 alvherre Exp $ -->
<chapter id="maintenance">
<title>Routine Database Maintenance Tasks</title>
</para>
<para>
- There is a limit of <xref linkend="guc-autovacuum-max-workers"> worker
- processes that may be running at any time, so if the <command>VACUUM</>
- and <command>ANALYZE</> work to do takes too long to run, the deadline may
- be failed to meet for other databases. Also, if a particular database
- takes a long time to process, more than one worker may be processing it
- simultaneously. The workers are smart enough to avoid repeating work that
- other workers have done, so this is normally not a problem. Note that the
- number of running workers does not count towards the <xref
- linkend="guc-max-connections"> nor the <xref
- linkend="guc-superuser-reserved-connections"> limits.
+ The <xref linkend="guc-autovacuum-max-workers"> setting limits how many
+ workers may be running at any time. If several large tables all become
+ eligible for vacuuming in a short amount of time, all autovacuum workers
+ may end up vacuuming those tables for a very long time. This would result
+ in other tables and databases not being vacuumed until a worker became
+ available. There is also not a limit on how many workers might be in a
+ single database, but workers do try and avoid repeating work that has
+ already been done by other workers. Note that the number of running
+ workers does not count towards the <xref linkend="guc-max-connections"> nor
+ the <xref linkend="guc-superuser-reserved-connections"> limits.
</para>
<para>