Re: Vacuum looping?

From: "Steven Flatt" <steven(dot)flatt(at)gmail(dot)com>
To: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Vacuum looping?
Date: 2007-07-30 16:04:08
Message-ID: 357fa7590707300904u4c2eb219p87793b5d19730638@mail.gmail.com
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On 7/28/07, Jim C. Nasby <decibel(at)decibel(dot)org> wrote:
>
> What are your vacuum_cost_* settings? If you set those too aggressively
> you'll be in big trouble.

autovacuum_vacuum_cost_delay = 100
autovacuum_vacuum_cost_limit = 200

These are generally fine, autovacuum keeps up, and there is minimal impact
on the system.

vacuum_cost_delay = 100
vacuum_cost_limit = 1000

We set this cost_limit a little higher so that, in the few cases where we
have to intervene manually, vacuum runs faster.

The second pass on the vacuum means that maintenance_work_memory isn't
> large enough.

maintenance_work_mem is set to 256MB and I don't think we want to make this
any bigger by default. Like I say above, generally autovacuum runs fine.
If we do run into this situation again (lots of OOM queries and lots to
cleanup), we'll probably increase maintenance_work_mem locally and run a
vacuum in that session.

Good to know that vacuum was doing the right thing.

Thanks,
Steve

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