Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id D06BD1337B5D for ; Fri, 31 Dec 2010 07:52:15 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 32882-01 for ; Fri, 31 Dec 2010 11:52:04 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail148154.authsmtp.co.uk (outmail148154.authsmtp.co.uk [62.13.148.154]) by mail.postgresql.org (Postfix) with ESMTP id 29FDC1336FA7 for ; Fri, 31 Dec 2010 07:52:03 -0400 (AST) Received: from mail-c193.authsmtp.com (mail-c193.authsmtp.com [62.13.128.118]) by punt6.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id oBVBpxVa090739; Fri, 31 Dec 2010 11:51:59 GMT Received: from [192.168.0.2] ([81.5.146.37]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2) with ESMTP id oBVBpumf035902; Fri, 31 Dec 2010 11:51:56 GMT Subject: Re: Sync Rep Design From: Simon Riggs To: Joshua Tolley Cc: Aidan Van Dyk , Robert Treat , Stefan Kaltenbrunner , pgsql-hackers@postgresql.org In-Reply-To: <4d1d4d96.c605ec0a.1af2.ffffb7ef@mx.google.com> References: <1293729972.1892.23804.camel@ebony> <4D1CC47E.7050207@kaltenbrunner.cc> <1293735853.1892.24886.camel@ebony> <4d1d4d96.c605ec0a.1af2.ffffb7ef@mx.google.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 31 Dec 2010 11:51:55 +0000 Message-ID: <1293796315.1892.37351.camel@ebony> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit X-Server-Quench: 5e7ed61f-14d4-11e0-97bb-002264978518 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCdxZQATClZOTQEd DAteCiN5VAwpPBRK HVkIKg5MJUcNSQVJ NksacxtFawRbaVxS HGQLWlREUVx7XGJ/ bg0fZQRDZ1RPWwN0 U09WR1pVCwUmXm5n dF5bD09ydABPeHw+ bUZkWz5eCUMvIUB8 FFNVETkCeGZhPWAC WUcKJR5UcAFIeBtM bVh6VXtDAzANdhEY NiQQEgoKCH1kOSJe CjsANRo+TF0KEThU X-Authentic-SMTP: 61633235383639.1014:706 X-AuthFastPath: 0 (Was 255) X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-5 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201012/2544 X-Sequence-Number: 177806 On Thu, 2010-12-30 at 20:26 -0700, Joshua Tolley wrote: > 2) initiate fsync on the primary first > > - In this case, the slave is always slightly behind. If if your > > primary falls over, you don't give commit messages to the clients, > but > > if it recovers, it might have committed data, and slaves will still > be > > able to catch up. > > > > The thing is that currently, even without replication, #2 can > happen. > > For what little it's worth, I vote for this option, because it's a > problem that can already happen (as opposed to adding an entirely new > type of problem to the mix). This proposal provides #2, so your wish is met. -- Simon Riggs http://www.2ndQuadrant.com/books/ PostgreSQL Development, 24x7 Support, Training and Services