X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 23E999FA38E for ; Wed, 10 May 2006 16:26:14 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 49187-10 for ; Wed, 10 May 2006 16:26:00 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from peufeu.com (boutiquenumerique.com [82.67.9.10]) by postgresql.org (Postfix) with ESMTP id 6D5BF9FA2CB for ; Wed, 10 May 2006 16:25:59 -0300 (ADT) Received: (qmail 1586 invoked from network); 10 May 2006 21:27:22 +0200 Received: from boutiquenumerique.com (HELO apollo13) (82.67.9.10) by boutiquenumerique.com with SMTP; 10 May 2006 21:27:22 +0200 Date: Wed, 10 May 2006 21:27:21 +0200 To: pgsql-hackers@postgresql.org Subject: Re: [PERFORM] Big IN() clauses etc : feature proposal References: <1147110142.32369.7.camel@archimedes> <20060508175013.GY99570@pervasive.com> <28288.1147111196@sss.pgh.pa.us> <20060509105214.P90693@vesihiisi.cksoft.de> <20060509113337.M90693@vesihiisi.cksoft.de> <20060509103632.GD29652@svana.org> <20060510190617.GP99570@pervasive.com> From: PFC Content-Type: text/plain; format=flowed; delsp=yes; charset=utf-8 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID: In-Reply-To: <20060510190617.GP99570@pervasive.com> User-Agent: Opera M2/8.51 (Linux, build 1462) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/282 X-Sequence-Number: 83147 > Have you tried getting a profile of what exactly PostgreSQL is doing > that takes so long when creating a temp table? Nope, I'm not proficient in the use of these tools (I stopped using C some time ago). > BTW, I suspect catalogs might be the answer, Probably, because : - Temp tables don't use fsync (I hope) - Catalogs do - fsync=off makes COMMIT fast - fsync=on makes COMMIT slow - fsync=on and using ANALYZE makes COMMIT slower (more updates to the catalogs I guess) > which is why Oracle has you > define a temp table once (which does all the work of putting it in the > catalog) and then you just use it accordingly in each individual > session. Interesting (except for the ANALYZE bit...)