Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bZEzs-0002HA-OE for pgsql-hackers@arkaria.postgresql.org; Mon, 15 Aug 2016 10:19:57 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1bZEzs-00064m-2q for pgsql-hackers@arkaria.postgresql.org; Mon, 15 Aug 2016 10:19:56 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1bZEzr-00064g-GT for pgsql-hackers@postgresql.org; Mon, 15 Aug 2016 10:19:55 +0000 Received: from newmail.postgrespro.ru ([93.174.131.138] helo=mail.postgrespro.ru) by makus.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bZEzo-0003qX-Rm for pgsql-hackers@postgresql.org; Mon, 15 Aug 2016 10:19:54 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.postgrespro.ru (Postfix) with ESMTP id 0E50721C2CC4; Mon, 15 Aug 2016 13:19:51 +0300 (MSK) X-Virus-Scanned: Debian amavisd-new at postgrespro.ru Received: from mail.postgrespro.ru ([127.0.0.1]) by localhost (mail.postgrespro.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TYneKr4kFZJo; Mon, 15 Aug 2016 13:19:50 +0300 (MSK) Received: from e733 (unknown [192.168.27.1]) by mail.postgrespro.ru (Postfix) with ESMTPSA id D6D2821C2863; Mon, 15 Aug 2016 13:19:50 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=postgrespro.ru; s=mail; t=1471256390; bh=DzxyBYYMW5c5kVTu/RavvGjTw8Kfd4Q7eijdDog6lb4=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=GNlOucyUKDBxGk9+K/wbJbv8E3a0C0/Y4IWhPWEtIafi6cHYWShZJzMli20UfPFJw LiVLD2nM5u8xGgXyivbiPjO1DUGDWwijX1bdLIjmk/2AZTtX1+vNhyf4NJgZFsw1hH eVU5RyWvD0rjHdlcl2rMchKkhuhvtBX2retx5AAs= Date: Mon, 15 Aug 2016 13:18:38 +0300 From: Aleksander Alekseev To: Pavel Stehule Cc: PostgreSQL Hackers , Andres Freund , Tom Lane , Robert Haas , Dmitry Dolgov <9erthalion6@gmail.com>, Tomas Vondra , David Steele Subject: Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables) Message-ID: <20160815131838.592c5667@e733> In-Reply-To: References: <20160801124531.66cde374@fujitsu> <26c3bc60-6613-e7ab-517a-53136f01fb6c@2ndquadrant.com> <13191.1470072250@sss.pgh.pa.us> <20160804151451.6fb87507@fujitsu> <14212.1470595566@sss.pgh.pa.us> <20160815005755.gswdyjfob7dzw4yp@alap3.anarazel.de> <20319.1471223097@sss.pgh.pa.us> <20160815010852.5ijua2wm2edzimd4@alap3.anarazel.de> <20160815120136.6f9c8dd1@e733> <20160815130004.72effe70@e733> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -2.5 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org > The global temporary tables has persistent rows in the catalogue. The > mapping to files can be marked as special and real mapping should be > only in memory. > > So the changes in catalogue related to global temporary tables are > pretty less frequently. I'm afraid I still don't get it. Let say I have an application that does `CREATE TEMP TABLE xx ; DROP TABLE xx` in every session all the time. Naturally there is not only one temp table per session. Could you explain please in more detail how exactly do these persistent rows help? -- Best regards, Aleksander Alekseev -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers