Received: from magus.postgresql.org ([87.238.57.229]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TbBln-00063E-2d for pgsql-performance@postgresql.org; Wed, 21 Nov 2012 14:59:19 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TbBlj-0005ii-Su for pgsql-performance@postgresql.org; Wed, 21 Nov 2012 14:59:18 +0000 Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.5/8.14.5) with ESMTP id qALEx7VN003397; Wed, 21 Nov 2012 09:59:07 -0500 (EST) From: Tom Lane To: Andrew Dunstan cc: Heikki Linnakangas , Craig Ringer , Claudio Freire , Merlin Moncure , David Greco , "pgsql-performance@postgresql.org" Subject: Re: Poor performance using CTE In-reply-to: <50ACE970.7050701@dunslane.net> References: <187F6C10D2931A4386EE8E58E13857F612917154@BLUPRD0811MB413.namprd08.prod.outlook.com> <50AC1472.3050607@2ndQuadrant.com> <18123.1353455585@sss.pgh.pa.us> <50ACD166.1000507@vmware.com> <50ACE970.7050701@dunslane.net> Comments: In-reply-to Andrew Dunstan message dated "Wed, 21 Nov 2012 09:47:12 -0500" Date: Wed, 21 Nov 2012 09:59:07 -0500 Message-ID: <3396.1353509947@sss.pgh.pa.us> X-Pg-Spam-Score: -2.2 (--) X-Archive-Number: 201211/226 X-Sequence-Number: 48592 Andrew Dunstan writes: > If we're going to do it can we please come up with something more > intuitive and much, much more documented than "OFFSET 0"? And if/when we > do this we'll need to have big red warnings all over then release notes, > since a lot of people I know will need to do some extensive remediation > before moving to such a release. The probability that we would actually *remove* that behavior of OFFSET 0 is not distinguishable from zero. I'm not terribly excited about having an alternate syntax to specify an optimization fence, but even if we do create such a thing, there's no need to break the historical usage. regards, tom lane