Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 965C59FA12B; Fri, 1 Dec 2006 16:55:40 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-new, port 10024) with ESMTP id 34409-09; Fri, 1 Dec 2006 16:55:36 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 9B43A9F9F0E; Fri, 1 Dec 2006 16:55:35 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id kB1KtUZY003320; Fri, 1 Dec 2006 15:55:30 -0500 (EST) To: "Merlin Moncure" cc: "Heikki Linnakangas" , "Alvaro Herrera" , "Simon Riggs" , pgsql-hackers@postgresql.org, pgsql-core@postgresql.org Subject: Re: [CORE] FOR SHARE vs FOR UPDATE locks In-reply-to: References: <1144.1164924373@sss.pgh.pa.us> <1164962544.3778.847.camel@silverbirch.site> <20061201113711.GC30441@alvh.no-ip.org> <15834.1164985926@sss.pgh.pa.us> <45705E9C.2060003@enterprisedb.com> <534.1164994846@sss.pgh.pa.us> <45706A77.8030503@enterprisedb.com> <1128.1164998817@sss.pgh.pa.us> Comments: In-reply-to "Merlin Moncure" message dated "Fri, 01 Dec 2006 15:11:59 -0500" Date: Fri, 01 Dec 2006 15:55:30 -0500 Message-ID: <3319.1165006530@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200612/44 X-Sequence-Number: 94525 "Merlin Moncure" writes: > imo, the most likely scenario would be a begin/exception/end block in > pg/sql. i would venture to guess that very little true savepointing > happens in practice. maybe add a little note of caution pg/sql error > handling documentation? I mentioned exception blocks as a risk factor, but I think the right place to document it is under FOR UPDATE/SHARE: http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select.sgml.diff?r1=1.93;r2=1.94 regards, tom lane