Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id A47F72E2E83 for ; Wed, 26 Dec 2007 17:52:10 -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 70508-03 for ; Wed, 26 Dec 2007 17:52:07 -0400 (AST) Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.180]) by postgresql.org (Postfix) with ESMTP id 1AC2C2E20AF for ; Wed, 26 Dec 2007 17:52:05 -0400 (AST) Received: by wa-out-1112.google.com with SMTP id m38so4480870waf.5 for ; Wed, 26 Dec 2007 13:52:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=31Cby5emYicg0f+wtZ7LBZU7r6o2YIB/nL4mvygINk0=; b=gb5mLYNGqLzWmB6H67x+5Y7whPy8YuP3xdRWJmnNriI4f3GUzniHMK2f65edIs24IHZcfaUfnAucX8rlx84hE2oMIFzAVlpNtIUy13tWVvsc8Hy7aC1W9h6ff3CWa0HjA+OSVzLfV1v/Aip8mg3aFlAkZCdIfaLNbI33od0NizE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=bS5Mj+u+yD7l5QwC8YCYLrxg7r7uY3+KpxvR/mb1ecYCOPwvgZ2LOt4/sbN7DUUX6QRiybrqWVtHfyJ76mTXFLnhA5RbPC53+YFtxT+4TBqPouKZIYTLvQ8C0OfYK7FQQtvpv1hA+uimfDT+E+9AE82jxjtVgp/w2XxjyHiKNVI= Received: by 10.114.112.1 with SMTP id k1mr1031106wac.24.1198705924070; Wed, 26 Dec 2007 13:52:04 -0800 (PST) Received: by 10.114.155.9 with HTTP; Wed, 26 Dec 2007 13:52:04 -0800 (PST) Message-ID: <1d4e0c10712261352j2fbcd25ek1270331468d824b4@mail.gmail.com> Date: Wed, 26 Dec 2007 22:52:04 +0100 From: "Guillaume Smet" To: "Greg Smith" Subject: Re: More shared buffers causes lower performances Cc: pgsql-performance In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1d4e0c10712251606q6f9503deye3da4b68c51bf5e@mail.gmail.com> <1198668065.4221.288.camel@ebony.site> <1d4e0c10712260741w1f141fd6x2f482143d526ad48@mail.gmail.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200712/380 X-Sequence-Number: 28196 On Dec 26, 2007 7:23 PM, Greg Smith wrote: > Ah, now this is really interesting, as it rules out all the write > components and should be easy to replicate even on a smaller server. As > you've already dumped a bunch of time into this the only other thing I > would suggest checking is whether the same behavior also happens on 8.2 on > your server. Let's go with 8.2.5 on the same server (-s 100 / 16 clients / 50k transactions per client / only read using -S option): 64MB: 33814 tps 512MB: 35833 tps 1024MB: 36986 tps It's more consistent with what I expected. I used PGDG RPMs compiled by Devrim for 8.2.5 and the ones I compiled myself for 8.3b4 (based on the src.rpm of Devrim). I just asked Devrim to build a set of x86_64 RPMs for 8.3b4 to see if it's not a compilation problem (they were compiled on a brand new box freshly installed so it would be a bit surprising but I want to be sure). He's kindly uploading them right now so I'll work on new tests using his RPMs. I'll keep you informed of the results. -- Guillaume