From: Jim C. Nasby <jnasby@pervasive.com>
To: Christopher Browne <cbbrowne@acm.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Default autovacuum settings too conservative
Date: Tue, 7 Feb 2006 01:26:21 -0600
Message-ID: <20060207072621.GI13592@pervasive.com> (raw)
In-Reply-To: <m38xsn4rvm.fsf@mobile.int.cbbrowne.com>
References: <20060201211633.GM95850@pervasive.com>
<43E12A03.6070906@zeut.net>
<20060207050545.GZ1240@pervasive.com>
<m38xsn4rvm.fsf@mobile.int.cbbrowne.com>
On Mon, Feb 06, 2006 at 10:14:53PM -0800, Christopher Browne wrote:
> > On Wed, Feb 01, 2006 at 04:37:07PM -0500, Matthew T. O'Connor wrote:
> >> I think the default settings should be designed to minimize the impact
> >> autovacuum has on the system while preventing the system from ever
> >> getting wildly bloated (also protect xid wraparound, but that doesn't
> >> have anything to do with the thresholds).
> >
> > I don't really see the logic behind that. Problems caused by inadequate
> > vacuuming seem to be much more prevalent than problems caused by vacuum
> > impacting the system. If vacuum impact is a concern I think it more
> > reasonable to make the default vacuum_cost_delay non-zero instead.
>
> That's a good point.
>
> I would not be keen, on the other hand, on having the delays terribly
> high.
>
> Big tables, if delayed significantly, will take plenty longer to
> vacuum, and I always get paranoid about long running transactions :-).
Very true, but I'd hope anyone running a table large enough for this to
make a difference would have done some tuning of their own...
What we really need is a replacement for vacuum_delay that takes
PostgreSQL generated IO activity into account...
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.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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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, cbbrowne@acm.org
Subject: Re: Default autovacuum settings too conservative
In-Reply-To: <20060207072621.GI13592@pervasive.com>
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