Re: about explain analyze

From: "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Teodor Sigaev <teodor(at)sigaev(dot)ru>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: about explain analyze
Date: 2003-11-28 17:00:33
Message-ID: 20031128125719.Q41642@ganymede.hub.org
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On Fri, 28 Nov 2003, Tom Lane wrote:

> Teodor Sigaev <teodor(at)sigaev(dot)ru> writes:
> > Explain analyze takes 3 times more time for execution. Why?
>
> Measurement overhead. It would seem your platform has a particularly
> slow version of gettimeofday() though ... I've never noticed such a
> large discrepancy myself.

Actually, I'm noticing similar "problems" with v7.4 ... "EXPLAIN ANALYZE"
seems to be showing some *very* high ms for execution time, but if you run
the actual query, it doesn't seem to take even 1/10th the time reported
...

This is on a FreeBSD 4.x box ...

----
Marc G. Fournier Hub.Org Networking Services (http://www.hub.org)
Email: scrappy(at)hub(dot)org Yahoo!: yscrappy ICQ: 7615664

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