Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id E48D69FB5D4 for ; Mon, 2 Jul 2007 19:21:44 -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 41465-09 for ; Mon, 2 Jul 2007 19:21:40 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id 7D8909FB446 for ; Mon, 2 Jul 2007 19:21:40 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l62MLffa015029 for ; Mon, 2 Jul 2007 18:21:41 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l62MLe4r015026 for ; Mon, 2 Jul 2007 18:21:40 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Mon, 2 Jul 2007 18:21:40 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-performance@postgresql.org Subject: Re: PostgreSQL 8.0 occasionally slow down In-Reply-To: <97e6e20f0706281904v4b7c4a97p570deda85e590ee4@mail.gmail.com> Message-ID: References: <97e6e20f0706272354m5e42c91em177c8b80abb2ea52@mail.gmail.com> <468361A9.1040308@archonet.com> <97e6e20f0706280101y543b871ao4cbf85e57f07f7e9@mail.gmail.com> <46836B66.7050109@archonet.com> <97e6e20f0706280117h20ab2e03n770abc588f17742@mail.gmail.com> <46837C50.20603@archonet.com> <97e6e20f0706281904v4b7c4a97p570deda85e590ee4@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/4 X-Sequence-Number: 25688 On Fri, 29 Jun 2007, Ho Fat Tsang wrote: > I noticed that for each time the pgsql slow down, there is a short > period a process called "pdflush" eating up lot of I/O. I've goolgled > and know it is a process for writing dirty pages back to the disk by the > Linux kernel. The pdflush documentation is really spread out, you may find my paper at http://www.westnet.com/~gsmith/content/linux-pdflush.htm a good place to start looking into that. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD