Re: stable functions

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От Filip Rembiałkowski
Тема Re: stable functions
Дата
Msg-id 92869e660705310423p32def3d4k54c156600fdd622b@mail.gmail.com
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Ответ на stable functions  (Vincenzo Romano <vincenzo.romano@gmail.com>)
Ответы Re: stable functions  (Vincenzo Romano <vincenzo.romano@gmail.com>)
Список pgsql-general
2007/5/31, Vincenzo Romano <vincenzo.romano@gmail.com>:
> Hi all.
>
> Can functions whose effect is to create functions (yep!)
> be labelled as "stable"?

According to the docs, no.

"STABLE indicates that the function cannot modify the database (...)
any function that has side-effects must be classified volatile"

http://www.postgresql.org/docs/8.2/static/sql-createfunction.html

If you labeled creatorfunc(param) as stable, ant then issued "SELECT
creatorfunc(sometable.param) FROM sometable", there is a theoretical
risk that creatorfunc would be called only _once_ for each distinct
value of param.




--
Filip Rembiałkowski

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