Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 728EF9FBD48; Thu, 29 Mar 2007 16:17:08 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 11297-01; Thu, 29 Mar 2007 16:16:57 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by postgresql.org (Postfix) with ESMTP id 0E7349FBE36; Thu, 29 Mar 2007 15:45:08 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [64.81.245.111] (account josh@agliodbs.com HELO [192.168.1.27]) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP-TLS id 11775406; Thu, 29 Mar 2007 10:49:12 -0800 From: Josh Berkus Reply-To: josh@agliodbs.com Organization: Aglio Database Solutions To: pgsql-hackers@postgresql.org Subject: Re: [PATCHES] Full page writes improvement, code update Date: Thu, 29 Mar 2007 11:45:27 -0700 User-Agent: KMail/1.8 Cc: "Simon Riggs" , "Koichi Suzuki" , pgsql-patches@postgresql.org References: <460886E8.6040907@oss.ntt.co.jp> <4609CAC3.7060008@oss.ntt.co.jp> <1175072848.4386.323.camel@silverbirch.site> In-Reply-To: <1175072848.4386.323.camel@silverbirch.site> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703291145.28574.josh@agliodbs.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200703/1733 X-Sequence-Number: 101217 Simon, > 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. -- --Josh Josh Berkus PostgreSQL @ Sun San Francisco