Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WcUC4-0005xs-Me for pgsql-performance@arkaria.postgresql.org; Tue, 22 Apr 2014 06:28:36 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1WcUC3-0001QN-WB for pgsql-performance@arkaria.postgresql.org; Tue, 22 Apr 2014 06:28:36 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WcUC3-0001QH-4I for pgsql-performance@postgresql.org; Tue, 22 Apr 2014 06:28:35 +0000 Received: from smtp-outbound-2.vmware.com ([208.91.2.13]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WcUBz-0001xo-73 for pgsql-performance@postgresql.org; Tue, 22 Apr 2014 06:28:33 +0000 Received: from sc9-mailhost2.vmware.com (sc9-mailhost2.vmware.com [10.113.161.72]) by smtp-outbound-2.vmware.com (Postfix) with ESMTP id 917F828764; Mon, 21 Apr 2014 23:28:29 -0700 (PDT) Received: from zcs-prod-ext-mta-2.vmware.com (zcs-prod-ext-mta-2.vmware.com [10.113.62.224]) by sc9-mailhost2.vmware.com (Postfix) with ESMTP id 8D8D9B0FFA; Mon, 21 Apr 2014 23:28:29 -0700 (PDT) Received: from zcs-prod-ext-mta-2.vmware.com (localhost.localdomain [127.0.0.1]) by zcs-prod-ext-mta-2.vmware.com (Postfix) with ESMTP id 2F263C004F; Mon, 21 Apr 2014 23:28:21 -0700 (PDT) Received: from [192.168.1.90] (zimbra-prod-ext-proxy-vip.vmware.com [10.113.63.87]) by zcs-prod-ext-mta-2.vmware.com (Postfix) with ESMTPSA; Mon, 21 Apr 2014 23:28:20 -0700 (PDT) Message-ID: <53560C07.80207@vmware.com> Date: Tue, 22 Apr 2014 09:28:23 +0300 From: Heikki Linnakangas Organization: VMware User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.4.0 MIME-Version: 1.0 To: obartunov@gmail.com, Laurence Parry CC: pgsql-performance@postgresql.org Subject: Re: Workaround: Planner preference for tsquery filter vs. GIN index in fast text search References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -7.6 (-------) 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 On 04/20/2014 07:46 AM, Oleg Bartunov wrote: > btw, 9.4 should be wiser in case of rare+common terms, thanks to GIN > fast scan feature. Indeed, although we didn't actually do anything to the planner to make it understand when fast scan helps. Doing something about cost estimation is still on the 9.4 Open Items list, but I don't have any ideas on what to do about it, and I haven't heard anything from Alexander about that either. That means that the cost estimation issue Laurence saw is going to be even worse in 9.4, because GIN is going to be faster than a seq scan in more cases than before and the planner doesn't know about it. - Heikki -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance