Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 6670E1336FA7 for ; Wed, 29 Dec 2010 11:18:50 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 35634-06 for ; Wed, 29 Dec 2010 15:18:45 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id C2AAB133616B for ; Wed, 29 Dec 2010 11:18:42 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id oBTFIfFk010250; Wed, 29 Dec 2010 10:18:41 -0500 (EST) To: bock@openit.de (Julian v. Bock) cc: pgsql-performance@postgresql.org Subject: Re: long wait times in ProcessCatchupEvent() In-reply-to: References: Comments: In-reply-to bock@openit.de (Julian v. Bock) message dated "Wed, 29 Dec 2010 15:28:34 +0100" Date: Wed, 29 Dec 2010 10:18:41 -0500 Message-ID: <10249.1293635921@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201012/327 X-Sequence-Number: 41779 bock@openit.de (Julian v. Bock) writes: > I have the problem that on our servers it happens regularly under a > certain workload (several times per minute) that all backend processes > get a SIGUSR1 and spend several seconds in ProcessCatchupEvent(). This is fixed in 8.4 and up. http://archives.postgresql.org/pgsql-committers/2008-06/msg00227.php If you aren't willing to move off 8.3 you might be able to ameliorate the problem by reducing the volume of catalog changes, but that can be pretty hard if you're dependent on temp tables. regards, tom lane