Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 981BF9FBEED for ; Fri, 20 Jul 2007 16:13:28 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 10002-01 for ; Fri, 20 Jul 2007 16:13:15 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id E04999FBD90 for ; Fri, 20 Jul 2007 16:13:17 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l6KJDDa0012446; Fri, 20 Jul 2007 15:13:13 -0400 (EDT) To: "Jignesh K. Shah" cc: Josh Berkus , pgsql-performance@postgresql.org, Alvaro Herrera Subject: Re: User concurrency thresholding: where do I look? In-reply-to: <46A1055F.9010304@sun.com> References: <200707190828.59088.josh@agliodbs.com> <200707191819.13899.josh@agliodbs.com> <15685.1184895926@sss.pgh.pa.us> <200707192138.39679.josh@agliodbs.com> <46A0FA31.2080208@sun.com> <12002.1184955831@sss.pgh.pa.us> <46A1055F.9010304@sun.com> Comments: In-reply-to "Jignesh K. Shah" message dated "Fri, 20 Jul 2007 14:56:31 -0400" Date: Fri, 20 Jul 2007 15:13:13 -0400 Message-ID: <12445.1184958793@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/272 X-Sequence-Number: 25956 "Jignesh K. Shah" writes: > Yes I did see increase in context switches and CPU migrations at that > point using mpstat. So follow that up --- try to determine which lock is being contended for. There's some very crude code in the sources that you can enable with -DLWLOCK_STATS, but probably DTrace would be a better tool. regards, tom lane