Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 052EB9FBA9E for ; Mon, 14 May 2007 10:34:27 -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 50015-04 for ; Mon, 14 May 2007 10:34:21 -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 686079FB9EF for ; Mon, 14 May 2007 10:34:21 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l4EDYLwH013067 for ; Mon, 14 May 2007 09:34:21 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l4EDYL3D013064 for ; Mon, 14 May 2007 09:34:21 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Mon, 14 May 2007 09:34:21 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-patches@postgresql.org Subject: Re: Automatic adjustment of bgwriter_lru_maxpages In-Reply-To: <20070514174531.71E0.ITAGAKI.TAKAHIRO@oss.ntt.co.jp> Message-ID: References: <461E108D.6080709@enterprisedb.com> <20070514174531.71E0.ITAGAKI.TAKAHIRO@oss.ntt.co.jp> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200705/182 X-Sequence-Number: 2282 On Mon, 14 May 2007, ITAGAKI Takahiro wrote: > BTW, your patch will cut LRU writes short, but will not encourage to > do more works. So should set more aggressive values to bgwriter_lru_percent > and bgwriter_lru_maxpages as defaults? Setting a bigger default maximum is one possibility I was thinking about. Since the whole background writer setup is kind of complicated, the other thing I was working on is writing a guide on how to use the new pg_stat_bgwriter information to figure out if you need to increase bgwriter_[all|lru]_pages (and the other parameters too). It makes it much easier to write that if you can say "You can safely set bgwriter_lru_maxpages high because it only writes what it needs to based on your usage". -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD