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Reword paragraph about the autovacuum_max_workers setting. Patch from

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Jim Nasby.
This commit is contained in:
Alvaro Herrera 2007-07-23 17:22:00 +00:00
parent b9ab88243e
commit aa81c558ee
1 changed files with 11 additions and 11 deletions
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22
doc/src/sgml/maintenance.sgml
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@ -1,4 +1,4 @@
<!-- $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>
@ -496,16 +496,16 @@ HINT: Stop the postmaster and use a standalone backend to VACUUM in "mydb".
</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>