Re: Automatic optimization of IN clauses via INNER JOIN

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От Robert Haas
Тема Re: Automatic optimization of IN clauses via INNER JOIN
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Msg-id 603c8f070912180723s14f374eew466928def9fa6a54@mail.gmail.com
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Ответ на Re: Automatic optimization of IN clauses via INNER JOIN  (Grzegorz Jaśkiewicz <gryzman@gmail.com>)
Ответы Re: Automatic optimization of IN clauses via INNER JOIN  (Grzegorz Jaśkiewicz <gryzman@gmail.com>)
Список pgsql-performance
2009/12/18 Grzegorz Jaśkiewicz <gryzman@gmail.com>:
> On Fri, Dec 18, 2009 at 2:18 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>
>> NOT IN is the only that really kills you as far as optimization is
>> concerned.  IN can be transformed to a join.  NOT IN forces a NOT
>> (subplan)-type plan, which bites - hard.
>
> in a well designed database (read: not abusing NULLs) - it can be done
> with joins too.

But not by PostgreSQL, or so I believe.

...Robert

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