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 61D3DDB6B0 for ; Tue, 22 Nov 2005 16:37:50 -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 17304-07 for ; Tue, 22 Nov 2005 20:37:50 +0000 (GMT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from koolancexeon.g2switchworks.com (mail.g2switchworks.com [63.87.162.25]) by svr1.postgresql.org (Postfix) with ESMTP id A515BDB48E for ; Tue, 22 Nov 2005 16:37:47 -0400 (AST) Received: mail.g2switchworks.com 10.10.1.8 from 10.10.1.37 10.10.1.37 via HTTP with MS-WebStorage 6.5.6944 Received: from state.g2switchworks.com by mail.g2switchworks.com; 22 Nov 2005 14:37:47 -0600 Subject: Re: High context switches occurring From: Scott Marlowe To: Anjan Dave Cc: Tom Lane , Vivek Khera , Postgresql Performance In-Reply-To: <4BAFBB6B9CC46F41B2AD7D9F4BBAF785098E76@vt-pe2550-001.vantage.vantage.com> References: <4BAFBB6B9CC46F41B2AD7D9F4BBAF785098E76@vt-pe2550-001.vantage.vantage.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1132691867.28788.42.camel@state.g2switchworks.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Tue, 22 Nov 2005 14:37:47 -0600 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.001 required=5 tests=[UNPARSEABLE_RELAY=0.001] X-Spam-Score: 0.001 X-Spam-Level: X-Archive-Number: 200511/456 X-Sequence-Number: 15713 On Tue, 2005-11-22 at 14:33, Anjan Dave wrote: > Is there any way to get a temporary relief from this Context Switching > storm? Does restarting postmaster help? > > It seems that I can recreate the heavy CS with just one SELECT > statement...and then when multiple such SELECT queries are coming in, > things just get hosed up until we cancel a bunch of queries... Is your machine a hyperthreaded one? Some folks have found that turning off hyper threading helps. I knew it made my servers better behaved in the past.