Re: Prepared query parsing much slower in 9.0?

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: "David E(dot) Wheeler" <david(at)kineticode(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Prepared query parsing much slower in 9.0?
Date: 2010-04-06 08:59:58
Message-ID: 4BBAF80E.3010306@dunslane.net
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David E. Wheeler wrote:
> When I run the Bricolage test suite against 8.4 (12,700 assertions), it takes 45-50s on my MacBook Pro. When I run them against 9.0, it takes 530-540s!
>
> Is there anything in the tree that has debugging turned on or something? I'm not at all sure that what Josh has found can account for this 10x difference, can it (I ran the tests several times).
>
> Looking at the process table, postgresql never goes over 25% CPU on 8.4, but hovers at 90-95% on 9.0. To judge by the way test output is emitted, writes are particularly slow, but I can see some substantial delays on reads, too.
>
>

This needs to be profiled. Otherwise we'd just be speculating on
possible causes with no real hard data. (This is where tools like
oprofile come in handy, but I have no idea if something similar is
available on OSX.)

cheers

andrew

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