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From: Joe Conway <mail@joeconway.com>
To: josh@agliodbs.com
Cc: pgsql-sql@postgresql.org
Subject: Re: How can I tell the performance difference?
Date: Thu, 16 May 2002 15:22:04 -0700
Message-ID: <3CE4310C.8030302@joeconway.com> (raw)
References: <200205161429.50058.josh@agliodbs.com>

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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