Re: Slow left outer join

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: Slow left outer join
Дата
Msg-id 963.1164591948@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Slow left outer join  (Alexander Staubo <alex@purefiction.net>)
Ответы Re: Slow left outer join
Список pgsql-general
Alexander Staubo <alex@purefiction.net> writes:
> select comments.*, users.*
> from comments
> left outer join users on
>    users.id = comments.creator_id
> inner join events_comments on
>    comments.id = events_comments.comment_id
>    and events_comments.event_id = 9244

> The outer join seems unnecessarily slow.

Try flipping the order of the two joins.  PG 8.2 will be smart enough to
do that for itself, but no existing release understands when it's safe
to rearrange outer-join order.

            regards, tom lane

В списке pgsql-general по дате отправления: