Re: Optimizing NOT IN plans / verify rewrite

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От Kevin Grittner
Тема Re: Optimizing NOT IN plans / verify rewrite
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Msg-id 4C56F47D0200002500034132@gw.wicourts.gov
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Ответ на Optimizing NOT IN plans / verify rewrite  (Maciek Sakrejda <msakrejda@truviso.com>)
Ответы Re: Optimizing NOT IN plans / verify rewrite  (Maciek Sakrejda <msakrejda@truviso.com>)
Список pgsql-performance
Kevin Grittner <Kgrittn@wicourts.gov> wrote:

> Maybe before I get excited I should try it with a query which is
> actually logically equivalent.

Fixed version:

DELETE FROM foo
  where type = 'o' and foo.b in (
  select b from foo WHERE type = 'o'
  except SELECT b FROM bar
  except SELECT b FROM foo where type <> 'o');

The change didn't affect run time significantly; it still beats the
others.

-Kevin


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