Re: LIMIT clause optimization - Mailing list pgsql-general

From Bruno Wolff III
Subject Re: LIMIT clause optimization
Date
Msg-id 20030107131658.GA6839@wolff.to
Whole thread Raw
In response to Re: LIMIT clause optimization  (Felipe Schnack <felipes@ritterdosreis.br>)
Responses Re: LIMIT clause optimization
List pgsql-general
On Tue, Jan 07, 2003 at 10:44:15 -0200,
  Felipe Schnack <felipes@ritterdosreis.br> wrote:
>   Why? I don't understand. If I create a query and want just the first
> row from it, wouldn't speed up things a lot just adding "LIMIT 1" in the
> end of the query?

That depends on the query. For some queries you will only see a small
speed up. It is also possible for limit to effect the optimization results
in a way that ends up slowing things down (though that should be rare)
because an inferior plan ends up being chosen.

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