X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id A54CF9DD55C for ; Tue, 6 Dec 2005 06:59:43 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 87946-01 for ; Tue, 6 Dec 2005 06:59:45 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) by postgresql.org (Postfix) with ESMTP id 03FD09DD4F5 for ; Tue, 6 Dec 2005 06:59:40 -0400 (AST) Received: from trofast.sesse.net ([129.241.93.32]) by cassarossa.samfundet.no with esmtp (Exim 4.50) id 1EjaXq-0006Cm-HP for pgsql-performance@postgresql.org; Tue, 06 Dec 2005 11:59:38 +0100 Received: from sesse by trofast.sesse.net with local (Exim 3.36 #1 (Debian)) id 1EjaXn-0005h8-00 for ; Tue, 06 Dec 2005 11:59:35 +0100 Date: Tue, 6 Dec 2005 11:59:35 +0100 From: "Steinar H. Gunderson" To: pgsql-performance@postgresql.org Subject: Re: BLCKSZ Message-ID: <20051206105935.GA21823@uio.no> Mail-Followup-To: pgsql-performance@postgresql.org References: <29518.1133794958@sss.pgh.pa.us> <4394B1D3.7000304@mail.ru> <6.2.5.6.0.20051205183120.01dd6a80@earthlink.net> <43956AAF.7060108@mail.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <43956AAF.7060108@mail.ru> X-Operating-System: Linux 2.6.14 on a x86_64 X-Message-Flag: Outlook? --> http://www.mozilla.org/products/thunderbird/ User-Agent: Mutt/1.5.11 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0 required=5 tests=[none] X-Spam-Score: 0 X-Spam-Level: X-Archive-Number: 200512/157 X-Sequence-Number: 15978 On Tue, Dec 06, 2005 at 01:40:47PM +0300, Olleg wrote: > I can't undestand why "bigger is better". For instance in search by > index. Index point to page and I need load page to get one row. Thus I > load 8kb from disk for every raw. And keep it then in cache. You > recommend 64kb. With your recomendation I'll get 8 times more IO > throughput, 8 time more head seek on disk, 8 time more memory cache (OS > cache and postgresql) become busy. Hopefully, you won't have eight times the seeking; a single block ought to be in one chunk on disk. You're of course at your filesystem's mercy, though. /* Steinar */ -- Homepage: http://www.sesse.net/