Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d3mKc-0007Ea-7J for pgsql-general@arkaria.postgresql.org; Thu, 27 Apr 2017 16:31:50 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1d3mKb-00088U-Ou for pgsql-general@arkaria.postgresql.org; Thu, 27 Apr 2017 16:31:49 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1d3mKa-00087k-Pz; Thu, 27 Apr 2017 16:31:48 +0000 Received: from lists.commandprompt.com ([2604:da00:2:2:5054:ff:fe07:7618]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1d3mKR-0002h7-UO; Thu, 27 Apr 2017 16:31:47 +0000 Received: from [192.168.1.50] (spinlock.commandprompt.com [69.168.55.30]) by lists.commandprompt.com (Postfix) with ESMTPA id 4DA331DF; Thu, 27 Apr 2017 09:31:35 -0700 (PDT) Received: from c-73-225-27-179.hsd1.wa.comcast.net ([73.225.27.179] helo=[192.168.1.50]) by assp.commandprompt.com with SMTPSA(TLSv1_2 ECDHE-RSA-AES128-GCM-SHA256) (2.5.1); 27 Apr 2017 09:31:34 -0700 Subject: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers. To: Andres Freund , pgsql-general@postgresql.org, pgsql-performance@postgresql.org References: <20170425041743.ddabv2mwevcmtx5a@alap3.anarazel.de> <20170427155906.uudovtd62x56brmx@alap3.anarazel.de> From: "Joshua D. Drake" Organization: Command Prompt, Inc. Message-ID: Date: Thu, 27 Apr 2017 09:31:34 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170427155906.uudovtd62x56brmx@alap3.anarazel.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Assp-Version: 2.5.1(16177) on assp.commandprompt.com X-Assp-ID: assp.commandprompt.com m1-10695-02118 X-Assp-Session: 7FF93CF9E398 (mail 1) X-Assp-Original-Subject: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers. X-Assp-Client-SSL: yes X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-general Precedence: bulk Sender: pgsql-general-owner@postgresql.org On 04/27/2017 08:59 AM, Andres Freund wrote: > > Ok, based on the, few, answers I've got so far, my experience is indeed > skewed. A number of the PG users I interacted with over the last couple > years had WAL write ranges somewhere in the range of 500MB/s to 2.2GB/s > (max I'veseen). At that point WAL insertion became a major bottleneck, > even if storage was more than fast enough to keep up. To address these > we'd need some changes, but the feedback so far suggest that it's not > yet a widespread issue... I would agree it isn't yet a widespread issue. The only people that are likely going to see this are going to be on bare metal. We should definitely plan on that issue for say 11. I do have a question though, where you have seen this issue is it with synchronous_commit on or off? Thanks, JD -- Command Prompt, Inc. http://the.postgres.company/ +1-503-667-4564 PostgreSQL Centered full stack support, consulting and development. Everyone appreciates your honesty, until you are honest with them. Unless otherwise stated, opinions are my own. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general