Re: 8.1 vs 8.2.1 view optimization

Поиск
Список
Период
Сортировка
От Martijn van Oosterhout
Тема Re: 8.1 vs 8.2.1 view optimization
Дата
Msg-id 20070116220455.GL8182@svana.org
обсуждение исходный текст
Ответ на Re: 8.1 vs 8.2.1 view optimization  (Nathan Bell <nathanb@actarg.com>)
Список pgsql-general
On Tue, Jan 16, 2007 at 02:55:08PM -0700, Nathan Bell wrote:
> Yeah, I saw the "not optimized out" typo as soon as I hit send.
>
> What if the item that is taking a long time isn't a function, but rather
> a sub-select?

The planner should be able to see that the item is non-volatile itself.
It only needs to be told for functions because it can't see into them.

> Can I set the sub-select to stable, or perhaps set the entire view to
> non-volatile to achieve the same result?

No.

> If not, can I set the sub-select to a different non-volatile view or do
> I need to create a non-volatile function that returns the result?

You could create a function that does the job, but that's generally not
necessary.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

Вложения

В списке pgsql-general по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: 8.1 vs 8.2.1 view optimization
Следующее
От: Alvaro Herrera
Дата:
Сообщение: Re: Multi-column constraint behaviour