Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XnykO-0002Zf-Km for pgsql-performance@arkaria.postgresql.org; Mon, 10 Nov 2014 23:51:48 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1XnykN-00074M-Ct for pgsql-performance@arkaria.postgresql.org; Mon, 10 Nov 2014 23:51:47 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1XnykL-000748-7l for pgsql-performance@postgresql.org; Mon, 10 Nov 2014 23:51:45 +0000 Received: from 01.zmailcloud.com ([192.198.85.104] helo=mx-out-1.zmailcloud.com) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XnykG-00005B-Pd for pgsql-performance@postgresql.org; Mon, 10 Nov 2014 23:51:44 +0000 Received: from smtp.01.com (smtp.01.com [10.10.0.43]) by mx-out-1.zmailcloud.com (Postfix) with ESMTP id 65B4A564D1E; Mon, 10 Nov 2014 17:51:38 -0600 (CST) Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 51D44603B5; Mon, 10 Nov 2014 17:51:38 -0600 (CST) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EhwdYBZO9RgP; Mon, 10 Nov 2014 17:51:38 -0600 (CST) Received: from smtp.01.com (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 1EA9B603CF; Mon, 10 Nov 2014 17:51:38 -0600 (CST) Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id F2CDC603C6; Mon, 10 Nov 2014 17:51:37 -0600 (CST) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id FnLBI-isoDSd; Mon, 10 Nov 2014 17:51:37 -0600 (CST) Received: from [172.19.131.110] (unknown [12.130.117.100]) by smtp-out-2.01.com (Postfix) with ESMTPSA id 7D170603B5; Mon, 10 Nov 2014 17:51:35 -0600 (CST) Message-ID: <54614F70.9040103@agliodbs.com> Date: Mon, 10 Nov 2014 15:51:12 -0800 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Jeff Janes CC: Tom Lane , Kevin Grittner , Andres Freund , Andrew Dunstan , Amit Kapila , "pgsql-performance@postgresql.org" Subject: Re: Performance bug in prepared statement binding in 9.2? References: <24236.1383940000@sss.pgh.pa.us> <1384014645.82057.YahooMailNeo@web162903.mail.bf1.yahoo.com> <19685.1384307200@sss.pgh.pa.us> <5283D433.3040406@agliodbs.com> <27642.1388512538@sss.pgh.pa.us> <54610878.3060203@agliodbs.com> <54610C41.4010504@agliodbs.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) 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 11/10/2014 12:13 PM, Jeff Janes wrote: > The related problem where the "end" rows are actually needed (e.g. ORDER > BY...LIMIT) has not been fixed. > > My idea to fix that was to check if the row's creation-transaction was in > the MVCC snapshot (which just uses local memory) before checking if that > creation-transaction had committed (which uses shared memory). But I > didn't really have the confidence to push that given the fragility of that > part of the code and my lack of experience with it. See "In progress > INSERT wrecks plans on table" thread. Oh! I thought this issue had been fixed by Tom's patch as well. It could very well describe what I'm seeing (in the other thread), since some of the waiting queries are INSERTs, and other queries do selects against the same tables concurrently. Although ... given that I'm seeing preposterously long BIND times (like 50 seconds), I don't think that's explained just by bad plans. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance