Re: Index on a NULL-value

От: Bruno Wolff III
Тема: Re: Index on a NULL-value
Дата: ,
Msg-id: 20050531040801.GA21334@wolff.to
(см: обсуждение, исходный текст)
Ответ на: Re: Index on a NULL-value  (Tobias Brox)
Список: pgsql-performance

Скрыть дерево обсуждения

Index on a NULL-value  (Tobias Brox, )
 Re: Index on a NULL-value  (Bruno Wolff III, )
  Re: Index on a NULL-value  (Tobias Brox, )
   Re: Index on a NULL-value  (Bruno Wolff III, )
 Re: Index on a NULL-value  (Tobias Brox, )
  Re: Index on a NULL-value  (Bruno Wolff III, )
   Re: Index on a NULL-value  (Tobias Brox, )
    Re: Index on a NULL-value  (Greg Stark, )
     Re: Index on a NULL-value  (Tom Lane, )
   Re: Index on a NULL-value  (Tom Lane, )
    Re: Index on a NULL-value  (Tobias Brox, )
 Re: Index on a NULL-value  (Tobias Brox, )

On Tue, May 31, 2005 at 11:31:58 +0800,
  Tobias Brox <> wrote:
> [Tobias Brox]
> > test=# set enable_seqscan=off;
>
> [Bruno Wolff III - Mon at 10:16:53PM -0500]
> > It isn't surprising that an index wasn't used since a sequential scan is
> > going to be faster in your test case.
> >
> > If you want to test this out, you to want use realistically sized tables.
>
> Wrong.  In this case I was not wondering about the planners choise of not
> using the index, but the fact that the planner could not find the index at
> all.  Reproducing it on a simple table in a test environment was a valid
> strategy to solve this specific problem.

I missed that you turned sequential scans off for your test.


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