Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1abta3-0003F9-1C for pgsql-performance@arkaria.postgresql.org; Fri, 04 Mar 2016 17:31:59 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84) (envelope-from ) id 1abta2-0005Ro-Hz for pgsql-performance@arkaria.postgresql.org; Fri, 04 Mar 2016 17:31:58 +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) (envelope-from ) id 1abtYK-0004vL-FZ; Fri, 04 Mar 2016 17:30:12 +0000 Received: from smtp4-g21.free.fr ([2a01:e0c:1:1599::13]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84) (envelope-from ) id 1abtYH-00072N-OG; Fri, 04 Mar 2016 17:30:12 +0000 Received: from [100.67.247.161] (unknown [37.161.223.98]) (Authenticated sender: ioguix) by smtp4-g21.free.fr (Postfix) with ESMTPSA id 209E74C8186; Fri, 4 Mar 2016 18:26:58 +0100 (CET) User-Agent: K-9 Mail for Android In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [ADMIN] autovacuum disk IO From: Jehan-Guillaume de Rorthais Date: Fri, 04 Mar 2016 18:28:02 +0100 To: Artem Tomyuk ,pgsql-admin@postgresql.org,pgsql-performance@postgresql.org Message-ID: X-Pg-Spam-Score: -2.6 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org Le 2 mars 2016 16:25:10 GMT+01:00, Artem Tomyuk a écrit : >Hi. > >I've noticed that autovac. process worked more than 10 minutes, during >this >zabbix logged more than 90% IO disk utilization on db volume.... > >===========>29237 2016-03-02 15:17:23 EET 00000 [24-1]LOG: >automatic vacuum of table "lb_upr.public._reference32": index scans: 1 > pages: 0 removed, 263307 remain > tuples: 298 removed, 1944753 remain, 0 are dead but not yet removable > buffer usage: 67814 hits, 265465 misses, 15647 dirtied > avg read rate: 3.183 MB/s, avg write rate: 0.188 MB/s According to what I am reading here, your autovacumm avg read activity was less than 4MB/s...and 188kB/s for writes. I seriously doubt these numbers are high enough to saturate your disks bandwidth. > *system usage: CPU 5.34s/6.27u sec elapsed 651.57 sec* This tells that the autovacumm tooks 651s to complete...but only 5s and 6s of cpu in kernel and userland in total. Autovacuum are slowed down thanks to autovacumm_vacuum_cost_delay param, which explains the 10min run and such a low disk activity. >Is it possible to log autovac. io impact during it execution? I would bet the problem is elsewhere... /Ioguix -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance