Subject: Re: How to determine cause of performance problem?
From: Joost Kraaijeveld <J.Kraaijeveld@Askesis.nl>
To: Michael Stone <mstone+postgres@mathom.us>
Cc: pgsql-performance@postgresql.org
In-Reply-To: <20050923095517.GW14918@mathom.us>
References: <1127458167.2475.105.camel@Panoramix>
	<20050923095517.GW14918@mathom.us>
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Date: Fri, 23 Sep 2005 12:21:15 +0200
Message-Id: <1127470875.3524.17.camel@Panoramix>
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On Fri, 2005-09-23 at 05:55 -0400, Michael Stone wrote:
> It's not clear what your object id generator does. If it's just a
> sequence, it's not clear that you need this program at all--just use a
> SELECT INTO and make the object id a SERIAL.
It generates a GUID (and no, I do not want to turn this in a discussion
about GUIDs). As in the Java code comment: it is not the generation of
the GUID that is the problem (that is, I can generate millions of them
per second.)

> If you do need to control the object id or do some other processing
> before putting the data into the new table, rewrite to use a COPY
> instead of an INSERT.
It is actually the shortest piece of code that gives me a poor
performance. The conversion problem is much, much larger and much much
more complicated. 

I suspect that either my hardware is to slow (but then again, see the
specs), or my Debian is to slow, or my PostgreSQL settings are wrong.

But I have no clue where to begin with determining the bottleneck (it
even may be a normal performance for all I know: I have no experience
with converting such (large) database).

Any suggestions?


-- 
Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
e-mail: J.Kraaijeveld@Askesis.nl
web: www.askesis.nl