To: Jeff Boes <jboes@nexcerpt.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Performance on temp table inserts 
In-reply-to: <1053434229.4973.1.camel@takin.private.nexcerpt.com> 
References: <baba9i$2vi8$1@news.hub.org> <26320.1053406306@sss.pgh.pa.us>
	<1053434229.4973.1.camel@takin.private.nexcerpt.com>
Comments: In-reply-to Jeff Boes <jboes@nexcerpt.com>
	message dated "20 May 2003 08:37:09 -0400"
Date: Tue, 20 May 2003 12:04:36 -0400
Message-ID: <29494.1053446676@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Jeff Boes <jboes@nexcerpt.com> writes:
>>> What factors affect the performance of a temp table insert?
>> 
>> PG version would have a lot to do with that, considering how we've
>> whacked around the temp-table implementation in the last few releases.

> PG version is 7.2.4.

IIRC, temp tables are really indistinguishable from regular tables in
7.2, as far as performance goes.  The bottleneck for the bare insert
itself would probably be WAL --- are you sure all the WAL settings are
the same on the two boxes?  If you have indexes, foreign keys, triggers,
rules, etc on the table then of course you have other overhead to worry
about ... but that seems somewhat unlikely for a temp table.

Also, is the temp table being filled in the same transaction that
created it, or in separate transaction(s)?  That makes a difference in
7.2 and before (but not in 7.3).

			regards, tom lane