Re: Index ot being used

Поиск
Список
Период
Сортировка
От Bruno Wolff III
Тема Re: Index ot being used
Дата
Msg-id 20050613030001.GB17491@wolff.to
обсуждение исходный текст
Ответ на Re: Index ot being used  (Madison Kelly <linux@alteeve.com>)
Ответы Re: Index ot being used  (Bruno Wolff III <bruno@wolff.to>)
Re: Index ot being used  (Madison Kelly <linux@alteeve.com>)
Список pgsql-performance
On Sun, Jun 12, 2005 at 18:52:05 -0400,
  Madison Kelly <linux@alteeve.com> wrote:
>
>   After sending that email I kept plucking away and in the course of
> doing so decided that I didn't need to return the 'file_type' column.
> Other than that, it would see my query now matches what you two have
> recommended in the 'ORDER BY...' front but I still can't get an index
> search.

No it doesn't. Even if you don't return file_type you still need it
in the order by clause if you want postgres to consider using your
index.

Is there some reason you didn't actually try out our suggestion, but are
now asking for more advice?

>
>   Here is the latest query and the new index:
>
> tle-bu=> \d file_info_7_display_idx;
> Index "public.file_info_7_display_idx"
>      Column      | Type
> -----------------+------
>  file_parent_dir | text
>  file_name       | text
> btree, for table "public.file_info_7"
>
> tle-bu=> EXPLAIN ANALYZE SELECT file_parent_dir, file_name, file_display
> FROM file_info_7 WHERE file_type='d' ORDER BY file_parent_dir ASC,
> file_name ASC;

В списке pgsql-performance по дате отправления:

Предыдущее
От: Mark Kirkwood
Дата:
Сообщение: Re: Updates on large tables are extremely slow
Следующее
От: Bruno Wolff III
Дата:
Сообщение: Re: Index ot being used