Re: pg_autovacuum w/ dbt2

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Mark Wong <markw(at)osdl(dot)org>
Cc: pgsql-hackers(at)postgresql(dot)org, testperf-general(at)pgfoundry(dot)org
Subject: Re: pg_autovacuum w/ dbt2
Date: 2004-12-21 23:50:52
Message-ID: 41C8B6DC.5060502@zeut.net
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Mark Wong wrote:

>The overall throughput is better for a run like this:
> http://www.osdl.org/projects/dbt2dev/results/dev4-010/207/
>
>A drop from 3865 to 2679 (31%) by just adding pg_autovacuum. That's
>what I meant by "not good". :)
>
>
I would agree that is "not good" :-) It sounds like pg_autovacuum is
being to aggressive for this type of load, that is vacuuming more often
than needed, however the lazy vacuum options were added so as to reduce
the performance impact of running a vacuum while doing other things, so,
I would recommend both higher autovacuum thresholds and trying out some
of the lazy vacuum settings.

>I'll start with the additional debug messages, with 8.0rc2, before
>I start changing the other settings, if that sounds good.
>

Sounds fine. From Tom Lane's response, we have a backend bug that needs
to be resolved and I think that is the priority.

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