X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [64.117.224.130]) by svr1.postgresql.org (Postfix) with ESMTP id 7FAA8D1C914 for ; Thu, 7 Aug 2003 21:16:01 +0000 (GMT) Received: from svr1.postgresql.org ([64.117.224.193]) by localhost (neptune.hub.org [64.117.224.130]) (amavisd-new, port 10024) with ESMTP id 29820-03 for ; Thu, 7 Aug 2003 18:14:37 -0300 (ADT) Received: from mail-1.zoominternet.net (mail-1.zoominternet.net [63.67.120.5]) by svr1.postgresql.org (Postfix) with SMTP id DE523D1C7F4 for ; Thu, 7 Aug 2003 18:15:49 -0300 (ADT) Received: (qmail 12860 invoked from network); 7 Aug 2003 21:15:51 -0000 Received: from acs-24-154-209-142.zoominternet.net (HELO gmod.lajolla) ([24.154.209.142]) (envelope-sender ) by mail-1.zoominternet.net (qmail-ldap-1.03) with SMTP for ; 7 Aug 2003 21:15:51 -0000 Subject: Re: EXTERNAL storage and substring on long strings From: Scott Cain To: Tom Lane Cc: Joe Conway , pgsql-performance@postgresql.org In-Reply-To: <8177.1060204101@sss.pgh.pa.us> References: <1059679600.1429.41.camel@localhost.localdomain> <7896.1060202191@sss.pgh.pa.us> <3F316A41.6020403@joeconway.com> <8177.1060204101@sss.pgh.pa.us> Content-Type: text/plain Organization: Cold Spring Harbor Lab Message-Id: <1060290951.6795.38.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.3 Date: 07 Aug 2003 17:15:51 -0400 Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at postgresql.org X-Archive-Number: 200308/145 X-Sequence-Number: 2962 > snipped much discussion about EXTERNAL storage and substring speed Joe and Tom, Thanks for all of your help; I went back to my (nearly) production database, and executed the `update feature set residues = residues ||'';` and then redid my benchmark. Here's a summary of the results: substr in perl 0.83sec/op substring on default text column 0.24sec/op substring on EXTERNAL column 0.0069sec/op There's that 2 orders of magnitude improvement I was looking for! Thanks again, Scott -- ------------------------------------------------------------------------ Scott Cain, Ph. D. cain@cshl.org GMOD Coordinator (http://www.gmod.org/) 216-392-3087 Cold Spring Harbor Laboratory