Re: join from array or cursor

Поиск
Список
Период
Сортировка
От Greg Stark
Тема Re: join from array or cursor
Дата
Msg-id 407d949e0908210616n2aa17ej48806379e427cb98@mail.gmail.com
обсуждение исходный текст
Ответ на Re: join from array or cursor  (John DeSoi <desoi@pgedit.com>)
Ответы Re: join from array or cursor
Список pgsql-general
On Fri, Aug 21, 2009 at 1:16 PM, John DeSoi<desoi@pgedit.com> wrote:
>
> Yes, this is the best I have come up with so far. I have a set returning
> function which returns the key and the index number. The implementation with
> a cursor looks like this:
>
> SELECT * FROM cursor_pk('c1') c LEFT JOIN foo ON (c.pk = foo.pk) ORDER BY
> c.idx;

This might be a circumstance where it's really best to just force the
planner to use a particular plan. There's no way to tell it "the order
of the array" without forcing an entirely unnecessary sort.

Something like
SET LOCAL enable_mergejoin = 'off';
SET LOCAL enable_hashjoin = 'off';
SELECT * from unnest(arr) as v(id) join tab using (id)
RESET ALL;

--
greg
http://mit.edu/~gsstark/resume.pdf

В списке pgsql-general по дате отправления:

Предыдущее
От: Grzegorz Jaśkiewicz
Дата:
Сообщение: Re: Temp table or normal table for performance?
Следующее
От: Greg Stark
Дата:
Сообщение: Re: join from array or cursor