Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 2A4056338D2 for ; Wed, 30 Sep 2009 03:33:58 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 31044-10 for ; Wed, 30 Sep 2009 06:33:50 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from exprod7og113.obsmtp.com (exprod7og113.obsmtp.com [64.18.2.179]) by mail.postgresql.org (Postfix) with SMTP id 8BEBD6326FA for ; Wed, 30 Sep 2009 03:33:49 -0300 (ADT) Received: from source ([209.85.219.216]) by exprod7ob113.postini.com ([64.18.6.12]) with SMTP ID DSNKSsL7zN7wqtFcjwnA0aRngQZlFGFCoYqJ@postini.com; Tue, 29 Sep 2009 23:33:49 PDT Received: by ewy12 with SMTP id 12so5600862ewy.24 for ; Tue, 29 Sep 2009 23:33:47 -0700 (PDT) Received: by 10.210.9.13 with SMTP id 13mr698626ebi.7.1254292427711; Tue, 29 Sep 2009 23:33:47 -0700 (PDT) Received: from ?192.168.1.117? (dsl-hkibrasgw2-ff67c300-165.dhcp.inet.fi [88.195.103.165]) by mx.google.com with ESMTPS id 7sm1350248eyg.41.2009.09.29.23.33.45 (version=TLSv1/SSLv3 cipher=RC4-MD5); Tue, 29 Sep 2009 23:33:46 -0700 (PDT) Message-ID: <4AC2FBC8.3060407@enterprisedb.com> Date: Wed, 30 Sep 2009 09:33:44 +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=-6.599 tagged_above=-10 required=5 tests=BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4 X-Spam-Level: X-Archive-Number: 200909/1926 X-Sequence-Number: 146732 Looking at the changes to StartupMultiXact, you're changing the locking so that both MultiXactOffsetControlLock and MultiXactMemberControlLock are acquired 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