Date: Wed, 30 Apr 2008 12:19:42 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Ian Westmacott <ianw@intellivid.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: 8.1.8 autovacuum missing databases
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Ian Westmacott wrote:
> On Tue, 2008-04-29 at 17:12 -0400, Alvaro Herrera wrote:
> > Can you verify whether age(pg_database.datfrozenxid) is shrinking after
> > vacuuming?  If the age() of a database is higher than the applicable
> > max_freeze_age, then it will always be chosen.
> 
> One of the databases is about 1.5TB, so that could take a while.
> Anything else I could look at in the meantime?  The age of these
> databases right now is about 290039577.  Also, autovacuum doesn't always
> choose the same DB, it alternates between template1 and one of mine --
> going back through a couple of months of logs I don't see it ever
> choosing the same one twice in a row.

Right -- if you have two databases over the wraparound edge, it will
alternate between them.

I still think that the autovac is dying before completing the task.  Did
you investigate whether there are "ERROR" messages coming from
autovacuum?  No PG crashes would happen.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support