X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 253F0DB122 for ; Thu, 27 Oct 2005 16:24:37 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 97662-06 for ; Thu, 27 Oct 2005 19:24:32 +0000 (GMT) Received: from flake.decibel.org (flake.decibel.org [67.100.216.10]) by svr1.postgresql.org (Postfix) with ESMTP id 46893DB0A1 for ; Thu, 27 Oct 2005 14:52:15 -0300 (ADT) Received: by flake.decibel.org (Postfix, from userid 1001) id 9A3191525E; Thu, 27 Oct 2005 12:52:15 -0500 (CDT) Date: Thu, 27 Oct 2005 12:52:15 -0500 From: "Jim C. Nasby" To: Richard Huxton Cc: mario.splivalo@mobart.hr, pgsql-sql@postgresql.org Subject: Re: why vacuum Message-ID: <20051027175215.GJ63747@pervasive.com> References: <200510261015.17623.lawgon@thenilgiris.com> <1130339980.2872.12.camel@state.g2switchworks.com> <435FAA21.3070400@Yahoo.com> <1130401371.31435.17.camel@ekim> <4360D44B.9020605@archonet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4360D44B.9020605@archonet.com> X-Operating-System: FreeBSD 4.11-RELEASE-p10 i386 X-Distributed: Join the Effort! http://www.distributed.net User-Agent: Mutt/1.5.9i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.008 required=5 tests=[AWL=0.008] X-Spam-Score: 0.008 X-Spam-Level: X-Archive-Number: 200510/375 X-Sequence-Number: 23228 On Thu, Oct 27, 2005 at 02:21:15PM +0100, Richard Huxton wrote: > So - if your statement contains something non-deterministic that isn't > catered for in Mysql's code then it will break. > > At it's simplest - if I write a function my_random() and then do: > UPDATE foo SET a=1 WHERE b < my_random(); > IF my_random() returns different results on different machines, then the > replication will be broken. See the manual entry below: > http://dev.mysql.com/doc/refman/5.0/en/replication-features.html > > That's not to say the system is worthless - it works fine for many > people. But it does have limitations. And you can easily have multi-master syncronous replication in PostgreSQL using the same idea; just see pgCluster. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461