Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 8FBBE2E01B9 for ; Thu, 13 Dec 2007 12:11:07 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 89609-09 for ; Thu, 13 Dec 2007 12:11:02 -0400 (AST) Received: from outmail129181.authsmtp.co.uk (outmail129181.authsmtp.co.uk [62.13.129.181]) by postgresql.org (Postfix) with ESMTP id 1CD662E01AE for ; Thu, 13 Dec 2007 12:11:01 -0400 (AST) Received: from outmail128179.authsmtp.co.uk (outmail128179.authsmtp.co.uk [62.13.128.179]) by punt3.authsmtp.com (8.13.8/8.13.8/Kp) with ESMTP id lBDGB02f029414; Thu, 13 Dec 2007 16:11:01 GMT Received: from [192.168.0.3] (85-211-24-246.dyn.gotadsl.co.uk [85.211.24.246]) (authenticated bits=0) by mail.authsmtp.com (8.13.8/8.13.8/Kp) with ESMTP id lBDGAxit061021; Thu, 13 Dec 2007 16:11:00 GMT Subject: Re: Heavy write activity on first vacuum of fresh TOAST data From: Simon Riggs To: Kevin Grittner Cc: pgsql-performance@postgresql.org In-Reply-To: <4760FF69.EE98.0025.0@wicourts.gov> References: <4760FF69.EE98.0025.0@wicourts.gov> Content-Type: text/plain Date: Thu, 13 Dec 2007 16:11:23 +0000 Message-Id: <1197562283.4255.1829.camel@ebony.site> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2 Content-Transfer-Encoding: 7bit X-Server-Quench: fec83ba9-a995-11dc-814e-001185d377ca X-AuthRoute: OCdxZQATClZOTQEd DAteCiNZVAwpPBRK HVkIKg5MJUcNSQVJ NksadBtFaQZbaVxS HGQLW1NEUVt7WGJ/ awofZQBDYEtPQQdu TkpNRE1QERpoT0Bz cmlvGkA2dwNHeHxx K0diV3IVChEpfUUv E0dJRGQPYHphaTRM TUhZc1ZJcANLfxdA PlN4UyBcLwdSbGoL JyIJERcLGAAXCClc XBBFMkgTXUtDFzUg Rg4DASRnGktNSSQp NABuNFcXAVsUekI8 eVU7VEkYeyM1IzZi fSBBCTNQT2wg X-Authentic-SMTP: 61633235383639.squirrel.dmpriest.net.uk:787/Kp X-Report-SPAM: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-Virus-Status: No virus detected - but ensure you scan with your own anti-virus system! X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200712/185 X-Sequence-Number: 28001 On Thu, 2007-12-13 at 09:46 -0600, Kevin Grittner wrote: > The data was inserted through a Java program using a prepared > statement with no indexes on the table. The primary key was then > added, and now I've started a vacuum. The new table wound up being > the first big table vacuumed, and I noticed something odd. Even > though there have been no rollbacks, updates, or deletes on this > table, the vacuum is writing as much as it is reading while dealing > with the TOAST data. Writing hint bits. Annoying isn't it? :-( -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com