From: Jim C. Nasby <jnasby@pervasive.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Zeugswetter Andreas DCP SD <ZeugswetterA@spardat.at>
Cc: PFC <lists@peufeu.com>
Cc: Greg Stark <gsstark@mit.edu>
Cc: pgsql-performance@postgresql.org
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Big IN() clauses etc : feature proposal
Date: Thu, 11 May 2006 17:58:42 -0500
Message-ID: <20060511225842.GZ99570@pervasive.com> (raw)
In-Reply-To: <4335.1147385316@sss.pgh.pa.us>
References: <E1539E0ED7043848906A8FF995BDA57901053F20@m0143.s-mxs.net>
<20060511210141.GP99570@pervasive.com>
<4335.1147385316@sss.pgh.pa.us>
On Thu, May 11, 2006 at 06:08:36PM -0400, Tom Lane wrote:
> "Jim C. Nasby" <jnasby@pervasive.com> writes:
> > I'd hope that wasn't what's happening... is the backend smart enough to
> > know not to fsync anything involved with the temp table?
>
> The catalog entries required for it have to be fsync'd, unless you enjoy
> putting your entire database at risk (a bad block in pg_class, say,
> would probably take out more than one table).
Yeah, thought about that after sending... :(
> It's interesting to speculate about keeping such catalog entries in
> child tables of pg_class etc that are themselves temp tables. Resolving
> the apparent circularity of this is left as an exercise for the reader.
Well, since it'd be a system table with a fixed OID there could
presumably be a special case in the recovery code for it, though that's
pretty fugly sounding.
Another alternative would be to support global temp tables... I think
that would handle all the complaints of the OP except for the cost of
analyze. I suspect this would be easier to do than creating a special
type of temp table that used tuplestore instead of the full table
framework, and it'd certainly be more general-purpose.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, tgl@sss.pgh.pa.us, ZeugswetterA@spardat.at, lists@peufeu.com, gsstark@mit.edu, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Big IN() clauses etc : feature proposal
In-Reply-To: <20060511225842.GZ99570@pervasive.com>
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