From: Thomas Finneid <tfinneid@student.matnat.uio.no>
To: pgsql-performance@postgresql.org
Subject: Re: insert vs select into performance
Date: Tue, 17 Jul 2007 22:58:01 +0200
Message-ID: <469D2D59.9030106@ifi.uio.no> (raw)
In-Reply-To: <5666.1184704280@sss.pgh.pa.us>
References: <469D1AD3.9030004@ifi.uio.no>
<0D6011B2-D09F-45E8-A5D7-5F84ADD1DC2B@seespotcode.net>
<5666.1184704280@sss.pgh.pa.us>
Tom Lane wrote:
> Michael Glaesemann <grzm@seespotcode.net> writes:
>> It would be helpful if you included the actual queries you're using,
>> as there are a number of variables:
>
> Not to mention which PG version he's testing.
Its pg 8.1, for now, I'll be upgrading to a compile optimised 8.2 when I
do the real test on the real server.
(its on kubuntu 6.10 running on a Thinkpad T60 with dual core 1.5,GB RAM
and 100GB SATA, just in case anybody feels that is of any interrest.)
> Since (I think) 8.1,
> SELECT INTO knows that it can substitute one fsync for WAL-logging
> the individual row inserts, since if there's a crash the new table
> will disappear anyway.
I am not sure I understand you correctly here, are you saying that
SELECT INTO in 8.1 disables WAL logging and uses just a single fsync at
the end? in that case it means that I could disable WAL as well and
achieve the same performance, does it not?
regards
thomas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: tfinneid@student.matnat.uio.no
Subject: Re: insert vs select into performance
In-Reply-To: <469D2D59.9030106@ifi.uio.no>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox