Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UulZR-0000iD-7Y for pgsql-hackers@arkaria.postgresql.org; Thu, 04 Jul 2013 15:35:45 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1UulZQ-0000Xz-LJ for pgsql-hackers@arkaria.postgresql.org; Thu, 04 Jul 2013 15:35:44 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UulZP-0000Wp-D3 for pgsql-hackers@postgresql.org; Thu, 04 Jul 2013 15:35:43 +0000 Received: from lists.commandprompt.com ([69.168.55.30]) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UulZK-0006lu-JF for pgsql-hackers@postgresql.org; Thu, 04 Jul 2013 15:35:43 +0000 Received: from [192.168.1.5] (spinlock.commandprompt.com [69.168.55.30]) by lists.commandprompt.com (Postfix) with ESMTPA id A7AA338F; Thu, 4 Jul 2013 08:35:35 -0700 (PDT) Received: from [192.168.1.5] ([71.95.101.172] helo=[192.168.1.5]) by assp.commandprompt.com with ESMTPS(AES256-SHA) (2.1.1); 4 Jul 2013 08:35:35 -0700 Message-ID: <51D59644.2070005@commandprompt.com> Date: Thu, 04 Jul 2013 08:35:32 -0700 From: "Joshua D. Drake" Organization: Command Prompt, Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Andres Freund CC: KONDO Mitsumasa , Robert Haas , Heikki Linnakangas , PostgreSQL-development Subject: Re: Improvement of checkpoint IO scheduler for stable transaction responses References: <51BEB6F5.7070907@lab.ntt.co.jp> <51C40EF4.1080201@lab.ntt.co.jp> <51C9D03B.10107@vmware.com> <51C9FD5C.5050706@vmware.com> <51CD873A.5070705@lab.ntt.co.jp> <51D3DE55.6030901@lab.ntt.co.jp> <51D56A5B.3050504@lab.ntt.co.jp> <20130704130555.GA1403@awork2.anarazel.de> In-Reply-To: <20130704130555.GA1403@awork2.anarazel.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Assp-Version: 2.1.1(11364) on assp.commandprompt.com X-Assp-Client-SSL: yes X-Assp-ID: assp.commandprompt.com m1-52135-01708 X-Assp-Envelope-From: jd@commandprompt.com X-Assp-Intended-For: andres@2ndquadrant.com X-Assp-Original-Subject: Re: [HACKERS] Improvement of checkpoint IO scheduler for stable transactionresponses X-Pg-Spam-Score: -2.1 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org On 07/04/2013 06:05 AM, Andres Freund wrote: >>> Presumably the smaller segsize is better because we don't >>> completely stall the system by submitting up to 1GB of io at once. So, >>> if we were to do it in 32MB chunks and then do a final fsync() >>> afterwards we might get most of the benefits. >> Yes, I try to test this setting './configure --with-segsize=0.03125' tonight. >> I will send you this test result tomorrow. > I did testing on this a few years ago, I tried with 2MB segments over 16MB thinking similarly to you. It failed miserably, performance completely tanked. JD -- Command Prompt, Inc. - http://www.commandprompt.com/ 509-416-6579 PostgreSQL Support, Training, Professional Services and Development High Availability, Oracle Conversion, Postgres-XC, @cmdpromptinc For my dreams of your image that blossoms a rose in the deeps of my heart. - W.B. Yeats -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers