Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 6543B1337E9A for ; Thu, 30 Dec 2010 17:17:06 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 15166-01-6 for ; Thu, 30 Dec 2010 21:16:58 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from cronos.madness.at (madness.at [217.196.146.217]) by mail.postgresql.org (Postfix) with ESMTP id C895E1337ECA for ; Thu, 30 Dec 2010 17:08:57 -0400 (AST) Received: from gatekeeper.kaltenbrunner.cc ([83.215.243.9] helo=[192.168.8.22]) by cronos.madness.at with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.69) (envelope-from ) id 1PYPju-0002bw-1P; Thu, 30 Dec 2010 22:08:52 +0100 Message-ID: <4D1CF4E2.5000208@kaltenbrunner.cc> Date: Thu, 30 Dec 2010 22:08:50 +0100 From: Stefan Kaltenbrunner User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101030 Iceowl/1.0b1 Icedove/3.0.10 MIME-Version: 1.0 To: Simon Riggs CC: Robert Treat , pgsql-hackers@postgresql.org Subject: Re: Sync Rep Design References: <1293729972.1892.23804.camel@ebony> <4D1CC47E.7050207@kaltenbrunner.cc> <1293735853.1892.24886.camel@ebony> <1293741390.1892.25918.camel@ebony> <1293742878.1892.26205.camel@ebony> In-Reply-To: <1293742878.1892.26205.camel@ebony> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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: 201012/2504 X-Sequence-Number: 177766 On 12/30/2010 10:01 PM, Simon Riggs wrote: > On Thu, 2010-12-30 at 15:51 -0500, Robert Treat wrote: > >> Still, one thing that has me concerned is that in the case of two >> slaves, you don't know which one is the more up-to-date one if you >> need to failover. It'd be nice if you could just guarantee they both >> are... > > Regrettably, nobody can know that, without checking. how exactly would you check? - this seems like something that needs to be done from the SQL and the CLI level and also very well documented (which I cannot see in your proposal). Stefan