X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 6EA7A52A3C for ; Mon, 18 Jul 2005 10:41:10 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 03547-07 for ; Mon, 18 Jul 2005 13:41:05 +0000 (GMT) Received: from rambo.iniquinet.com (rambo.iniquinet.com [69.39.89.10]) by svr1.postgresql.org (Postfix) with ESMTP id DA43D52CA9 for ; Mon, 18 Jul 2005 10:41:03 -0300 (ADT) Received: (qmail 32208 invoked by uid 1010); 18 Jul 2005 09:41:06 -0400 Received: from Robert_Creager@LogicalChaos.org by rambo.iniquinet.com by uid 1002 with qmail-scanner-1.20 (clamscan: 0.70. spamassassin: 3.0.3. Clear:RC:0(63.147.78.131):SA:0(?/?):. Processed in 4.074218 secs); 18 Jul 2005 13:41:06 -0000 Received: from unknown (HELO thunder.logicalchaos.org) (perl?test@logicalchaos.org@63.147.78.131) by rambo.iniquinet.com with AES256-SHA encrypted SMTP; 18 Jul 2005 09:41:02 -0400 Received: from logicalchaos.org (thunder.logicalchaos.org [192.168.0.250]) by thunder.logicalchaos.org (Postfix) with ESMTP id B5F0EB32C5; Mon, 18 Jul 2005 07:41:00 -0600 (MDT) Date: Mon, 18 Jul 2005 07:41:00 -0600 From: Robert Creager To: Tom Lane Cc: PGPerformance , Andy Hewitt Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS Message-ID: <20050718074100.3159e825@thunder.logicalchaos.org> In-Reply-To: <24520.1121659853@sss.pgh.pa.us> References: <20050717213416.59dcb52e@thunder.logicalchaos.org> <24520.1121659853@sss.pgh.pa.us> Organization: Starlight Vision, LLC. X-Mailer: Sylpheed-Claws 1.0.3 (GTK+ 1.2.10; i586-mandrake-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; boundary=Signature_Mon__18_Jul_2005_07_41_00_-0600_qIUf4mwaPMLUfx2w; protocol="application/pgp-signature"; micalg=pgp-sha1 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.001 tagged_above=0 required=5 tests=AWL X-Spam-Level: X-Archive-Number: 200507/257 X-Sequence-Number: 13498 --Signature_Mon__18_Jul_2005_07_41_00_-0600_qIUf4mwaPMLUfx2w Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable When grilled further on (Mon, 18 Jul 2005 00:10:53 -0400), Tom Lane 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? >=20 Ran 7 hours on 741 with VACUUM ANALYZE every 5 minutes. The largest CS I s= aw 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 VAC= UUM 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 wit= h the VACUUM FULL, I'll turn off the vacuum delay. Cheers, Rob --=20 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 --Signature_Mon__18_Jul_2005_07_41_00_-0600_qIUf4mwaPMLUfx2w Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iEYEARECAAYFAkLbsWwACgkQLQ/DKuwDYzktbQCfZ39U38nwHZ/2Kme20kghS5fe 9F8AnigtFAQ1h9A/WQn2V53aWivWiMNR =MFbd -----END PGP SIGNATURE----- --Signature_Mon__18_Jul_2005_07_41_00_-0600_qIUf4mwaPMLUfx2w--