Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 0A1516326DC for ; Wed, 30 Sep 2009 03:33:48 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 41810-10 for ; Wed, 30 Sep 2009 06:33:34 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from exprod7og104.obsmtp.com (exprod7og104.obsmtp.com [64.18.2.161]) by mail.postgresql.org (Postfix) with SMTP id B47276322D5 for ; Wed, 30 Sep 2009 03:33:36 -0300 (ADT) Received: from source ([209.85.219.228]) by exprod7ob104.postini.com ([64.18.6.12]) with SMTP ID DSNKSsL7v+IzPc/PV7cFKJ3MbJFIzosg4MOR@postini.com; Tue, 29 Sep 2009 23:33:36 PDT Received: by ewy28 with SMTP id 28so12737292ewy.18 for ; Tue, 29 Sep 2009 23:33:34 -0700 (PDT) Received: by 10.210.9.5 with SMTP id 5mr5625696ebi.78.1254292414669; Tue, 29 Sep 2009 23:33:34 -0700 (PDT) Received: from ?192.168.1.117? ([88.195.103.165]) by mx.google.com with ESMTPS id 7sm1383192eyb.36.2009.09.29.23.33.31 (version=TLSv1/SSLv3 cipher=RC4-MD5); Tue, 29 Sep 2009 23:33:32 -0700 (PDT) Message-ID: <4AC2FBB9.7060304@enterprisedb.com> Date: Wed, 30 Sep 2009 09:33:29 +0300 From: Heikki Linnakangas Organization: EnterpriseDB User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: Simon Riggs CC: pgsql-hackers Subject: Re: Hot Standby on git References: <1253958559.4449.833.camel@ebony.2ndQuadrant> In-Reply-To: <1253958559.4449.833.camel@ebony.2ndQuadrant> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.427 tagged_above=-10 required=5 tests=AWL=0.172, BAYES_00=-2.599 X-Spam-Level: X-Archive-Number: 200909/1925 X-Sequence-Number: 146731 Looking at the changes to StartupMultiXact, you're changing the locking so that both MultiXactOffsetControlLock and MultiXactMemberControlLock are acquire first before changing anything. Why? Looking at the other functions in that file, all others that access both files are happy to acquire one lock at a time, like StartupMultiXact does without the patch. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com