Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 6BE4063446D for ; Wed, 23 Jun 2010 16:30:10 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 96660-10 for ; Wed, 23 Jun 2010 19:30:03 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from exprod7og103.obsmtp.com (exprod7og103.obsmtp.com [64.18.2.159]) by mail.postgresql.org (Postfix) with SMTP id 569FA631ADA for ; Wed, 23 Jun 2010 16:30:02 -0300 (ADT) Received: from source ([74.125.82.44]) by exprod7ob103.postini.com ([64.18.6.12]) with SMTP ID DSNKTCJgtf8wHWAMgyMjM4bt7rUBrPKv9YhX@postini.com; Wed, 23 Jun 2010 12:30:02 PDT Received: by wwi17 with SMTP id 17so893766wwi.31 for ; Wed, 23 Jun 2010 12:29:57 -0700 (PDT) Received: by 10.227.138.134 with SMTP id a6mr7948415wbu.14.1277321396968; Wed, 23 Jun 2010 12:29:56 -0700 (PDT) Received: from [192.168.1.117] (dsl-hkibrasgw2-ff7ac300-240.dhcp.inet.fi [88.195.122.240]) by mx.google.com with ESMTPS id t15sm63872835wbc.5.2010.06.23.12.29.55 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 23 Jun 2010 12:29:56 -0700 (PDT) Message-ID: <4C2260B2.8040305@enterprisedb.com> Date: Wed, 23 Jun 2010 22:29:54 +0300 From: Heikki Linnakangas Organization: EnterpriseDB User-Agent: Mozilla/5.0 (X11; U; Linux i686; fi-FI; rv:1.9.1.9) Gecko/20100515 Iceowl/1.0b1 Icedove/3.0.4 MIME-Version: 1.0 To: Robert Haas CC: Simon Riggs , Joshua Tolley , pgsql-docs Subject: Re: hot standby documentation References: <4c20b2ed.0134e70a.19ef.5b22@mx.google.com> <1277319234.25074.2466.camel@ebony> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-4.2 tagged_above=-5 required=5 tests=BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3 X-Spam-Level: X-Archive-Number: 201006/64 X-Sequence-Number: 5632 On 23/06/10 22:05, Robert Haas wrote: > On Wed, Jun 23, 2010 at 2:53 PM, Simon Riggs wrote: >> We could also allow SELECT ... FOR SHARE during Hot Standby, simply by >> making it same as normal SELECT, without any ill effects. > > True. Not really. It won't matter while the standby is in read-only mode, but as soon as the server is promoted to master, you could have other backends modifying rows that the still-running "SELECT ... FOR SHARED" transaction should have locked. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com