Re: How can I tell the performance difference?

From: Joe Conway <mail(at)joeconway(dot)com>
To: josh(at)agliodbs(dot)com
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: How can I tell the performance difference?
Date: 2002-05-16 22:22:04
Message-ID: 3CE4310C.8030302@joeconway.com
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Josh Berkus wrote:
> Folks,
>
> I have a view which will be used very, very often in my database. As such, I
> need to evaluate which of the two following structures is the best for that
> view. However, I can't easily figure out which of the two explain plans
> looks more costly. Can anybody help?
>

I would use PHP (or Perl or something) to generate some sample data
(i.e. a few hundred thousand records or so) and then use EXPLAIN ANALYZE
(after VACUUM ANALYZE of course ;-) ), instead of trying to guess
performance based on EXPLAIN output that won't be relevant once you have
data.

Just my 2 cents . . .

Joe

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