Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id CEECC1337C03 for ; Wed, 13 Apr 2011 15:43:52 -0300 (ADT) 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 44513-04-4; Wed, 13 Apr 2011 18:43:45 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 6DDE81337C31; Wed, 13 Apr 2011 15:43:03 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id p3DIgvpq010018; Wed, 13 Apr 2011 14:42:57 -0400 (EDT) To: Simon Riggs cc: =?ISO-8859-1?Q?Devrim_G=DCND=DCZ?= , raghu ram , pgsql-admin , pgsql-general Subject: Re: Streaming Replication limitations In-reply-to: References: <1302717319.8788.4.camel@lenovo01-laptop03.gunduz.org> <9304.1302718017@sss.pgh.pa.us> Comments: In-reply-to Simon Riggs message dated "Wed, 13 Apr 2011 19:34:47 +0100" Date: Wed, 13 Apr 2011 14:42:57 -0400 Message-ID: <10017.1302720177@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=2.409 tagged_above=-10 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: 201104/134 X-Sequence-Number: 37315 Simon Riggs writes: > 2011/4/13 Tom Lane : >> Short answer is to test the case you have in mind and see. > That's the long answer, not least because the absence of a failure in > a test is not conclusive proof that it won't fail at some point in the > future while in production. Not really. Every known source of incompatibility (endianness, alignment, float format, etc) is checked at postmaster startup via entries in pg_control. If you get the slave postmaster to start at all, it will probably work, though certainly more extensive testing than that would be advisable. > The short answer is "don't do it". DBAs are paid to be incredibly paranoid, and from that mindset this answer makes sense. But there's a big difference between "it won't work" and "I'm afraid to risk my paycheck on this because there might possibly be some problem that no one knows about yet". Let's be perfectly clear that this is a question of the second case not the first. regards, tom lane