Received: from localhost (maia-3.hub.org [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 9317E9FBFEE; Thu, 29 Mar 2007 17:46:25 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 03305-03-6; Thu, 29 Mar 2007 17:46:02 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from mail01.enterprisedb.com (mail01.enterprisedb.com [63.246.7.168]) by postgresql.org (Postfix) with ESMTP id 057D59FBFA3; Thu, 29 Mar 2007 17:32:25 -0300 (ADT) thread-index: AcdyQWPxGDOehKxoQWKEZzwpWz4hoQ== Received: from [192.168.0.22] ([85.211.147.35]) by mail01.enterprisedb.com with Microsoft SMTPSVC(6.0.3790.1830); Thu, 29 Mar 2007 16:32:36 -0400 Content-Class: urn:content-classes:message Importance: normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.2826 Subject: Re: [PATCHES] Full page writes improvement, code update From: "Simon Riggs" To: Cc: , "Koichi Suzuki" , In-Reply-To: <200703291145.28574.josh@agliodbs.com> References: <460886E8.6040907@oss.ntt.co.jp> <4609CAC3.7060008@oss.ntt.co.jp> <1175072848.4386.323.camel@silverbirch.site> <200703291145.28574.josh@agliodbs.com> Content-Type: text/plain; charset="iso-8859-1" Date: Thu, 29 Mar 2007 21:28:36 +0100 Message-ID: <1175200117.4386.616.camel@silverbirch.site> MIME-Version: 1.0 X-Mailer: Evolution 2.6.0 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 29 Mar 2007 20:32:36.0890 (UTC) FILETIME=[635E17A0:01C77241] X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200703/1740 X-Sequence-Number: 101224 On Thu, 2007-03-29 at 11:45 -0700, Josh Berkus wrote: > > OK, different question: > > Why would anyone ever set full_page_compress = off? > > The only reason I can see is if compression costs us CPU but gains RAM & > I/O. I can think of a lot of applications ... benchmarks included ... > which are CPU-bound but not RAM or I/O bound. For those applications, > compression is a bad tradeoff. > > If, however, CPU used for compression is made up elsewhere through smaller > file processing, then I'd agree that we don't need a switch. Koichi-san has explained things for me now. I misunderstood what the parameter did and reading your post, ISTM you have as well. I do hope Koichi-san will alter the name to allow everybody to understand what it does. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com