Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 7515F6331DC for ; Sun, 25 Apr 2010 00:02:57 -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 54990-06 for ; Sun, 25 Apr 2010 03:02:47 +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 9E3C8632D92 for ; Sun, 25 Apr 2010 00:02:46 -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 o3P32geo019875; Sat, 24 Apr 2010 23:02:42 -0400 (EDT) To: Robert Haas cc: Jim Nasby , Greg Sabino Mullane , pgsql-hackers@postgresql.org Subject: Re: global temporary tables In-reply-to: References: <7796.1272125493@sss.pgh.pa.us> <9319.1272130283@sss.pgh.pa.us> <18126.1272159451@sss.pgh.pa.us> <19198.1272162480@sss.pgh.pa.us> Comments: In-reply-to Robert Haas message dated "Sat, 24 Apr 2010 22:57:01 -0400" Date: Sat, 24 Apr 2010 23:02:42 -0400 Message-ID: <19874.1272164562@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201004/1148 X-Sequence-Number: 161260 Robert Haas writes: > Pushing it into the RelFileNode has some advantages in terms of being > able to get at the information from everywhere, but one thing that > makes me think that's probably not a good decision is that we somtimes > WAL-log relfilenodes. And WAL-logging the value of the isTemp flag is > a waste, because if we're WAL-logging, it's zero. Yeah. I think we also use RelFileNode as a hash tag in places, and so adding a bool to it would be problematic for a couple of reasons: possibly uninitialized pad bytes, and uselessly incorporating more bytes into the hash calculation. regards, tom lane