Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id C72EB9FB4EC for ; Tue, 15 May 2007 09:45:21 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 42179-09 for ; Tue, 15 May 2007 09:45:12 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.4 Received: from nz-out-0506.google.com (nz-out-0506.google.com [64.233.162.226]) by postgresql.org (Postfix) with ESMTP id 77B6F9FB5B4 for ; Tue, 15 May 2007 09:45:17 -0300 (ADT) Received: by nz-out-0506.google.com with SMTP id s1so134934nze for ; Tue, 15 May 2007 05:45:16 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=VVlJSl4BUstpm3QjRNbRCqHyWeo3V78C/6ATf4tnS97vqpRrXCNfwMQbpw/cuhei9buizrgWhCDPyGL+/m5vd/joZ/m5k0nNQ9Rh+SKGOfS80sv31vCd95axKnsdoEtSH7T71CcShah62kfMBY0drnFjOXcCV1WmDtaX7syahbM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=gWMOo1sHe6KE0Nia5sf0d4UeP8x5Q0Z1x4CRi1RcRVYELtlTutnnXHK4ri+iXf63q96Dh9FuZNPzF8BztzK3F+M72InJTzew+Z4oz3kZNSTH482d+rUidSzGMjVa9ASLJpd0+9uCG61yqKDYMmbVD9l2waID55nx6NuBTqhWS0U= Received: by 10.65.203.3 with SMTP id f3mr748799qbq.1179233115991; Tue, 15 May 2007 05:45:15 -0700 (PDT) Received: from ?172.24.32.112? ( [62.232.55.118]) by mx.google.com with ESMTP id q19sm489641qbq.2007.05.15.05.45.12; Tue, 15 May 2007 05:45:14 -0700 (PDT) Message-ID: <4649AB4F.8050209@enterprisedb.com> Date: Tue, 15 May 2007 13:45:03 +0100 From: Heikki Linnakangas User-Agent: Icedove 1.5.0.10 (X11/20070329) MIME-Version: 1.0 To: Greg Smith CC: pgsql-patches@postgresql.org Subject: Re: Automatic adjustment of bgwriter_lru_maxpages References: <461E108D.6080709@enterprisedb.com> <20070514174531.71E0.ITAGAKI.TAKAHIRO@oss.ntt.co.jp> <9814.1179150750@sss.pgh.pa.us> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200705/214 X-Sequence-Number: 2314 Greg Smith wrote: > I realized recently the task I should take on here is to run some more > experiments with the latest code and pass along suggested techniques for > producing/identifying the kind of problem conditions I've run into in > the past; then we can see if other people can reproduce them. I got a > new 8-core server I need to thrash anyway and will try and do just that > starting tomorrow. Yes, please do that. I can't imagine a situation where a tunable maximum would help, but you've clearly spent a lot more time experimenting with it than me. I have noticed that on a heavily (over)loaded system with fully saturated I/O, bgwriter doesn't make any difference because all the backends need to wait for writes anyway. But it doesn't hurt either. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com