Message-ID: <43275F56.8020303@commandprompt.com>
Date: Tue, 13 Sep 2005 16:23:02 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
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To: pryscila.lista@gmail.com
Cc: pgsql-performance@postgresql.org
Subject: Re: About method of PostgreSQL's Optimizer
References: <cf0868bd05091315503024742@mail.gmail.com>
In-Reply-To: <cf0868bd05091315503024742@mail.gmail.com>
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Pryscila B Guttoski wrote:
> Hello all!
> 
> On my master course, I'm studying the PostgreSQL's optimizer.
> I don't know if anyone in this list have been participated from the 
> PostgreSQL's Optimizer development, but maybe someone can help me on 
> this question.
> PostgreSQL generates all possible plans of executing the query (using an 
> almost exhaustive search), then gives a cost to each plan and finally 
> the cheapest one is selected for execution.
> There are other methods for query optimization, one of them is based on 
> plan transformations (for example, using A-Star algorithm) instead of 
> plan constructions used by PostgreSQL.
> Does anyone know why this method was choosen? Are there any papers or 
> researches about it?

You may want to pass this question over to pgsql-hackers.

Sincerely,

Joshua D. Drake


> 
> Thank's a lot,
> Pryscila.


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