Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id D19376346E6 for ; Thu, 9 Jul 2009 05:09:23 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 61844-03-4 for ; Thu, 9 Jul 2009 05:09:08 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from relay.ptn-ipout01.plus.net (relay.ptn-ipout01.plus.net [212.159.7.35]) by mail.postgresql.org (Postfix) with ESMTP id 526ED633F33 for ; Thu, 9 Jul 2009 05:09:08 -0300 (ADT) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEAHtCVUrUnw6T/2dsb2JhbADQEIQIBQ Received: from ptb-relay03.plus.net ([212.159.14.147]) by relay.ptn-ipout01.plus.net with ESMTP; 09 Jul 2009 09:09:06 +0100 Received: from [84.51.143.99] (helo=server3.office.archonet.com) by ptb-relay03.plus.net with esmtp (Exim) id 1MOogk-0006AY-5t; Thu, 09 Jul 2009 09:09:06 +0100 Received: from dell36.office.archonet.com (dell36.office.archonet.com [192.168.1.36]) by server3.office.archonet.com (Postfix) with ESMTP id 018C7274074; Thu, 9 Jul 2009 09:09:05 +0100 (BST) Message-ID: <4A55A5A1.7000005@archonet.com> Date: Thu, 09 Jul 2009 09:09:05 +0100 From: Richard Huxton User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Rob Sargent CC: pgsql-sql@postgresql.org Subject: Re: Moving text columns, when it actually is large References: <4A550D5E.3020008@gmail.com> In-Reply-To: <4A550D5E.3020008@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Plusnet-Relay: a049cb9bfa05933b1ddb2769140726fd X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200907/39 X-Sequence-Number: 32780 Rob Sargent wrote: > I have to restructure some tables, coalescing common elements from three > tables (sub-classes) into a single table (super-class). Each source > table has a text field which actually gets stuffed with a largish (1Mb+) > blob of xml. > > Is there any way to simply, um, er, transplant the pointer rather than > actually copy the data? If they are large-objects (stored via the lo_xxx interface) yes. If not, no. I take it the large blob of xml is one of the fields that you are classifying as common? -- Richard Huxton Archonet Ltd