Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 266C61337B83 for ; Fri, 18 Mar 2011 18:24:25 -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 49969-05 for ; Fri, 18 Mar 2011 21:24:15 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from gw.wicourts.gov (gwmta.wicourts.gov [165.219.244.99]) by mail.postgresql.org (Postfix) with ESMTP id 703621337999 for ; Fri, 18 Mar 2011 18:24:14 -0300 (ADT) Received: from Courts-MTA by gw.wicourts.gov with Novell_GroupWise; Fri, 18 Mar 2011 16:24:13 -0500 Message-Id: <4D838723020000250003BAFB@gw.wicourts.gov> X-Mailer: Novell GroupWise Internet Agent 8.0.1 Date: Fri, 18 Mar 2011 16:24:03 -0500 From: "Kevin Grittner" To: "Simon Riggs" , "Robert Haas" Cc: "Markus Wanner" , "Alvaro Herrera" , "Andrew Dunstan" , "Heikki Linnakangas" , "MARK CALLAGHAN" , "Aidan Van Dyk" , "pgsql-hackers" Subject: Re: Re: [COMMITTERS] pgsql: Efficient transaction-controlled synchronous replication. References: <4D741441.2090704@dunslane.net> <1299454125.1696.6138.camel@ebony> <4D74896C.5030402@enterprisedb.com> <4D74DDFA.70800@dunslane.net> <4D74E584.7080409@enterprisedb.com> <4D74E9FA.7070202@dunslane.net> <4D74F3AE.9000802@dunslane.net> <4D74FDEC.5040406@enterprisedb.com> <4D74FF15.1070804@dunslane.net> <1299513979-sup-1987@alvh.no-ip.org> <4D832571.5030808@bluegap.ch> <1300457958.18619.13780.camel@ebony> <4D832B4D020000250003BA98@gw.wicourts.gov> <4D837EA2.2070205@enterprisedb.com> <1300465171.18619.15193.camel@ebony> <4D83B02A.5090105@bluegap.ch> <1300476590.18619.18115.camel@ebony> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=2.409 tagged_above=-5 required=5 tests=BAYES_00=-1.9, FS_REPLICA=3.599, SARE_SPEC_REPLICA=0.72, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: ** X-Archive-Number: 201103/1172 X-Sequence-Number: 184422 Robert Haas wrote: > Since the current solution is intended to support data-loss-free > failover, but NOT to guarantee a consistent view of the world from > a SQL level, I doubt it's worth paying any price for this. Well, that brings us back to the question of why we would want to suppress the view of the data on the master until the replica acknowledges the commit. It *is* committed on the master, we're just holding off on telling the committer about it until we can honor the guarantee of replication. If it can be seen on the replica before the committer get such acknowledgment, why not on the master? -Kevin