X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 374BFDB08A for ; Tue, 22 Nov 2005 13:35:53 -0400 (AST) 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 80862-08-2 for ; Tue, 22 Nov 2005 17:35:51 +0000 (GMT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by svr1.postgresql.org (Postfix) with ESMTP id 59C41DB09D for ; Tue, 22 Nov 2005 13:35:50 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id jAMHZnCB012639; Tue, 22 Nov 2005 12:35:49 -0500 (EST) To: Vivek Khera cc: Postgresql Performance , "Anjan Dave" Subject: Re: High context switches occurring In-reply-to: <0D46FCC7-9DB2-4B45-B7C3-4F76EF53DB1F@khera.org> References: <4BAFBB6B9CC46F41B2AD7D9F4BBAF785098E73@vt-pe2550-001.vantage.vantage.com> <0D46FCC7-9DB2-4B45-B7C3-4F76EF53DB1F@khera.org> Comments: In-reply-to Vivek Khera message dated "Tue, 22 Nov 2005 12:14:54 -0500" Date: Tue, 22 Nov 2005 12:35:49 -0500 Message-ID: <12638.1132680949@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.003 required=5 tests=[AWL=0.003] X-Spam-Score: 0.003 X-Spam-Level: X-Archive-Number: 200511/449 X-Sequence-Number: 15706 Vivek Khera writes: > On Nov 22, 2005, at 11:59 AM, Anjan Dave wrote: >> This is a Dell Quad XEON. Hyperthreading is turned on, and I am >> planning to turn it off as soon as I get a chance to bring it down. > You should probably also upgrade to Pg 8.0 or newer since it is a > known problem with XEON processors and older postgres versions. > Upgrading Pg may solve your problem or it may not. PG 8.1 is the first release that has a reasonable probability of avoiding heavy contention for the buffer manager lock when there are multiple CPUs. If you're going to update to try to fix this, you need to go straight to 8.1. I've recently been chasing a report from Rob Creager that seems to indicate contention on SubTransControlLock, so the slru code is likely to be our next bottleneck to fix :-( regards, tom lane