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 4E64B5294F for ; Mon, 16 May 2005 00:26:10 -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 70176-04 for ; Mon, 16 May 2005 03:26:01 +0000 (GMT) Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by svr1.postgresql.org (Postfix) with ESMTP id EA5485294E for ; Mon, 16 May 2005 00:26:00 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [63.195.55.98] (account josh@agliodbs.com HELO spooky) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 7366870; Sun, 15 May 2005 20:27:59 -0700 From: Josh Berkus Organization: Aglio Database Solutions To: "David Parker" Subject: Re: checkpoint segments Date: Sun, 15 May 2005 20:26:02 -0700 User-Agent: KMail/1.8 Cc: pgsql-performance@postgresql.org References: <07FDEE0ED7455A48AC42AC2070EDFF7C74609A@corpsrv2.tazznetworks.com> In-Reply-To: <07FDEE0ED7455A48AC42AC2070EDFF7C74609A@corpsrv2.tazznetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200505152026.02262.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.014 tagged_above=0 required=5 tests=AWL X-Spam-Level: X-Archive-Number: 200505/296 X-Sequence-Number: 12460 David, > I've seen these messages in the log before, and am aware of the need to > increase checkpoint_segments, but I wasn't aware that recycling a > transaction log could be that damaging to performance. There may have > been some local hiccup in this case, but I'm wondering if recycling is > known to be a big hit in general, and if I should strive to tune so that > it never happens (if that's possible)? Yes, and yes. Simply allocating more checkpoint segments (which can eat a lot of disk space -- requirements are 16mb*(2 * segments +1) ) will prevent this problem. -- Josh Berkus Aglio Database Solutions San Francisco