Re: Views- Advantages and Disadvantages

Поиск
Список
Период
Сортировка
От Richard Broersma Jr
Тема Re: Views- Advantages and Disadvantages
Дата
Msg-id 737058.4446.qm@web31807.mail.mud.yahoo.com
обсуждение исходный текст
Ответ на Re: Views- Advantages and Disadvantages  (Reece Hart <reece@harts.net>)
Список pgsql-general
--- Reece Hart <reece@harts.net> wrote:
> I believe that you're mistaken, and you can see it rather easily by
> explaining a select on a view (or even a view of views). For example:
>         View definition:
>          SELECT pa.palias_id, pv.pseq_id, pa.origin_id, pa.alias,
>         pa.descr, pa.tax_id, pv.ref_pseq_id, pv.added
>            FROM paliasorigin pa, pseqalias pv
>           WHERE pv.palias_id = pa.palias_id AND pv.is_current = true;

if you're only selectivity is "is_current = true", you will get a seq. scan no matter what.
However, I bet your explain plan would be much better if you added something like:

SELECT *
  FROM View
 WHERE origin_id = <some origin_id value>;

as long as you had an index on origin_id.

Regards,
Richard Broersma Jr.

В списке pgsql-general по дате отправления:

Предыдущее
От: Jeff Davis
Дата:
Сообщение: Re: Replication for PG 8 recommendations
Следующее
От: Brent Wood
Дата:
Сообщение: Re: Views- Advantages and Disadvantages