Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1ezL2Q-00075v-Cr for pgsql-performance@arkaria.postgresql.org; Fri, 23 Mar 2018 11:39:14 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1ezL2P-0004sy-7O for pgsql-performance@arkaria.postgresql.org; Fri, 23 Mar 2018 11:39:13 +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 4.89) (envelope-from ) id 1ezL2P-0004rM-00 for pgsql-performance@lists.postgresql.org; Fri, 23 Mar 2018 11:39:13 +0000 Received: from mout.kundenserver.de ([212.227.17.13]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1ezL2M-00050z-3u for pgsql-performance@lists.postgresql.org; Fri, 23 Mar 2018 11:39:12 +0000 Received: from [10.8.0.146] ([185.40.248.10]) by mrelayeu.kundenserver.de (mreue101 [212.227.15.145]) with ESMTPSA (Nemesis) id 0LhNR2-1eCmsO1z3A-00mafL for ; Fri, 23 Mar 2018 12:39:08 +0100 Subject: Re: Should from_collapse be switched off? (queries 10 times faster) To: pgsql-performance@lists.postgresql.org References: <20180323100308.GA1188@gate.oper.dinoex.org> From: Thomas Kellerer Message-ID: <71c6894e-f924-4aca-dad7-a22d19bb5b75@gmx.net> Date: Fri, 23 Mar 2018 12:39:07 +0100 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.23) Gecko/20090812 Thunderbird/2.0.0.23 Mnenhy/0.7.6.666 MIME-Version: 1.0 In-Reply-To: <20180323100308.GA1188@gate.oper.dinoex.org> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:lH/rbNshWdsnkTALDiHrYeLq4TwyiBEezGxhzPL8gaNLU7x0Nja wnr0ON8K46kjSD8D1bl8lxrlDl1eTKgcNFPhZwjOdcH/w2YRUzP0WGgxDAzTh+4ke/aE4XM smUsou5YgPFMXzQdtKp9uybfp05f5LHgBtGVusfQeJtX5WCEJOflJb9mjLXABhteQGt5x03 ac1R+Py+aGW/e3rWzLD4g== X-UI-Out-Filterresults: notjunk:1;V01:K0:GHVJIF80gow=:3SLUxJqkA0X2V+VKM2jvX9 KaA/2hN2dwuzf0oLTxLXrZvGkGosaYj4ZG4+kxzs0rUyBhgsKe/zm3gfPg1CzstqAsemMcOBw Wozzr+pwQVN+cRYgHiDibVhtUqdgjmQK3LolA5VP/DAaBDHfpwCcUoIbPeKDtvC8WZFtVqbNL 2Y4U6h+d370Tf0y+PSZmKoyR/Kba4gU0WfHOaME8DMa4ov21Hdxc0PMv0RXYQRRbOzG0aQQwE Ej3Lu6ne0qjv9G+3Y5EjK3tjWwuFmaRwpaaO75IQmP+Kz+i9zyUjHqHLBJYpqNsOfUaIahHdo d2ISWx/GE9OACtge0da7j4Qye+Xl1X6Xjuc7cucKcU0imZvWmKEhP5kHSG4K8SDzZsCm3qp2U rvhXcGDPP8uEZeEBwVK7swIT5VmZmZZFnSIMtEuoQ/JRxjGMCA384FrcvkRECev/igQOgHSm/ 2YrxRy85pd7UiGudYOxDSnQxDzwCEClpPFvScJNFwZtyrauE40KbmWC3PZn122GNiRSVxwTeV JgRCEVbtkjfrkL2WAKsvtdMxkXDHQFqQWHcJeqIsbjVWzJEhARPfp0mP9suncjVEAa1Rn2dhq 49ZU6FeKNGZrjhJJSShB+l99iIBFZh0mIlAa3k1TGGttYP0DbvO7CqNwieiOGRXLaecYz/8N6 wR7gHZais3TyFuqeK1WRd+t7act9mUy2mP5Mmd1W4L3asEEI1rc0UBXjL+rwZ2OnWqF+2FrZ1 P6GI+n4qiQWP7UT6Jgmf+jbwadQbD5fVisErWXrAuYCmi/iKC6iM1nNLvuw= List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk Peter schrieb am 23.03.2018 um 11:03: > My queries get up to 10 times faster when I disable from_collapse > (setting from_collapse_limit=1). > > After this finding, The pramatic solution is easy: it needs to be > switched off. You should post some example queries together with the slow and fast plans. Ideally generated using "explain(analyze, buffers)" instead of a simple "explain" to see details on the execution Thomas