From: Robert Creager <Robert_Creager@LogicalChaos.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PGPerformance <pgsql-performance@postgresql.org>
Cc: Andy Hewitt <Andy_Hewitt@StorageTek.com>
Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS
Date: Mon, 18 Jul 2005 07:41:00 -0600
Message-ID: <20050718074100.3159e825@thunder.logicalchaos.org> (raw)
In-Reply-To: <24520.1121659853@sss.pgh.pa.us>
References: <20050717213416.59dcb52e@thunder.logicalchaos.org>
<24520.1121659853@sss.pgh.pa.us>
When grilled further on (Mon, 18 Jul 2005 00:10:53 -0400),
Tom Lane <tgl@sss.pgh.pa.us> confessed:
> The context swap problem was no worse in 8.0 than in prior versions,
> so that hardly seems like a good explanation. Have you tried reverting
> to the cron-based vacuuming method you used in 7.4?
>
Ran 7 hours on 741 with VACUUM ANALYZE every 5 minutes. The largest CS I saw
was 40k, with an average of 500 (via script which monitors vmstat output).
I've done a VACUUM FULL ANALYZE on 803 and have switched the cron based VACUUM
ANALYZE to 803 also. The tests are now running again.
> Hmm, did you read this thread?
> http://archives.postgresql.org/pgsql-performance/2005-07/msg00088.php
I just glanced at it. Once I've reproduced (or not) the problem on 803 with the
VACUUM FULL, I'll turn off the vacuum delay.
Cheers,
Rob
--
07:10:06 up 4 days, 10:45, 6 users, load average: 0.28, 0.40, 0.29
Linux 2.6.5-02 #8 SMP Mon Jul 12 21:34:44 MDT 2004
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To: pgsql-performance@postgresql.org
Cc: Robert_Creager@LogicalChaos.org, tgl@sss.pgh.pa.us, Andy_Hewitt@StorageTek.com
Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS
In-Reply-To: <20050718074100.3159e825@thunder.logicalchaos.org>
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