Re: Huge performance problem between 7.4.1 and 8.0.3 - CS - Mailing list pgsql-performance

From Robert Creager
Subject Re: Huge performance problem between 7.4.1 and 8.0.3 - CS
Date
Msg-id 20050718074100.3159e825@thunder.logicalchaos.org
Whole thread Raw
In response to Re: Huge performance problem between 7.4.1 and 8.0.3 - CS issue?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
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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