Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 3B4AF6325E3 for ; Tue, 30 Mar 2010 14:51:10 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 50076-07 for ; Tue, 30 Mar 2010 17:50:59 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id A005C63223E for ; Tue, 30 Mar 2010 14:50:59 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id o2UHoujk026237; Tue, 30 Mar 2010 13:50:56 -0400 (EDT) To: Artiom Makarov cc: pgsql-performance@postgresql.org Subject: Re: temp table "on commit delete rows": transaction overhead In-reply-to: References: Comments: In-reply-to Artiom Makarov message dated "Tue, 30 Mar 2010 15:46:26 +0400" Date: Tue, 30 Mar 2010 13:50:56 -0400 Message-ID: <26236.1269971456@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.599 tagged_above=-10 required=5 tests=BAYES_00=-2.599 X-Spam-Level: X-Archive-Number: 201003/399 X-Sequence-Number: 38224 Artiom Makarov writes: > When temp tables with "on commit delete rows" exists, I can see a > strange delay at any “begin” and “commit”. A delay at commit is hardly surprising, because each such temp table requires filesystem operations at commit (basically an "ftruncate"). I don't recall any operations at transaction start for such tables, but there may be some. regards, tom lane