Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 66AFC9FB34E for ; Sat, 21 Jul 2007 01:26:32 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 22254-04 for ; Sat, 21 Jul 2007 01:26:29 -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 25B2E9FB308 for ; Sat, 21 Jul 2007 01:26:28 -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 l6L4QA1s020298; Sat, 21 Jul 2007 00:26:10 -0400 (EDT) To: David Boreham cc: "Jignesh K. Shah" , Josh Berkus , pgsql-performance@postgresql.org, Alvaro Herrera Subject: Re: User concurrency thresholding: where do I look? In-reply-to: <46A17E02.2090807@boreham.org> 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> <12445.1184958793@sss.pgh.pa.us> <46A11116.5030905@sun.com> <14909.1184962561@sss.pgh.pa.us> <46A1205B.8010205@sun.com> <15343.1184965054@sss.pgh.pa.us> <46A17E02.2090807@boreham.org> Comments: In-reply-to David Boreham message dated "Fri, 20 Jul 2007 21:31:14 -0600" Date: Sat, 21 Jul 2007 00:26:10 -0400 Message-ID: <20297.1184991970@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/282 X-Sequence-Number: 25966 David Boreham writes: > Tom Lane wrote: >> Having malloc/free use >> an internal mutex is necessary in multi-threaded programs, but the >> backend isn't multi-threaded. > Hmm...confused. I'm not following why then there is contention for the > mutex. There isn't any contention for that mutex; Jignesh's results merely show that it was taken and released a lot of times. regards, tom lane