Re: Help tuning autovacuum - seeing lots of relation bloat

From: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
To: jody brownell <jody(dot)brownell(at)q1labs(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Help tuning autovacuum - seeing lots of relation bloat
Date: 2006-06-21 18:57:53
Message-ID: 20060621185752.GD93655@pervasive.com
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On Wed, Jun 21, 2006 at 10:52:42AM -0300, jody brownell wrote:
> A db wide vacuum full outputs this at the end.
>
> INFO: free space map contains 32848 pages in 159 relations
> DETAIL: A total of 24192 page slots are in use (including overhead).
> 24192 page slots are required to track all free space.
> Current limits are: 4024000 page slots, 2000 relations, using 23705 KB.

FWIW, the tail end of a db-wide vacuum FULL doesn't provide useful info
about FSM utilization, because it just made everything as compact as
possible.

My suspicion is that it's taking too long for autovac to get around to
this database/table. Dropping the sleep time might help. I see that this
table is vacuumed with a delay setting of 0, but if there are other
tables with a high delay that could pose a problem.

Getting detailed output of what autovac is actually doing as Tom
suggested would be a good idea.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461

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