From: Michael Fuhr <mike@fuhr.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: John Lister <john.lister-ps@kickstone.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: controlling autovacuum during the day.
Date: Wed, 17 Dec 2008 08:29:03 -0700
Message-ID: <20081217152903.GA37436@winnie.fuhr.org> (raw)
In-Reply-To: <28510.1229525243@sss.pgh.pa.us>
References: <2BB7361E57C4417A975C0474610BA4C3@squarepi.com>
<27759.1229521625@sss.pgh.pa.us>
<742A9D77A1BA4171AF52BBBF6F5F2C75@squarepi.com>
<28510.1229525243@sss.pgh.pa.us>
On Wed, Dec 17, 2008 at 09:47:23AM -0500, Tom Lane wrote:
> "John Lister" <john.lister-ps@kickstone.com> writes:
> > Cheers for the quick reply. I've tweaked them quite a bit, but we have quite
> > a few heavily updated tables that i'd like vacuuming to keep them in check.
> > Unfortunately the autovacuum does a FULL vacuum every so often locking the
> > tables for quite a long time, i'd like to move these to the evening if
> > possible.
>
> Huh? Autovacuum *never* does VACUUM FULL.
Perhaps autovacuum is shrinking the table after finding lots of empty
pages at the end, as in what VACUUM VERBOSE is logging here:
INFO: "foo": truncated 11944384 to 8877366 pages
I think this acquires an AccessExclusiveLock. I've seen this take
hours in the case of a table with a lot of empty pages.
--
Michael Fuhr
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To: pgsql-admin@postgresql.org
Cc: mike@fuhr.org, tgl@sss.pgh.pa.us, john.lister-ps@kickstone.com
Subject: Re: controlling autovacuum during the day.
In-Reply-To: <20081217152903.GA37436@winnie.fuhr.org>
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