On Thursday, March 10, 2011 05:26:00 PM Julius Tuskenis wrote:
> 3) As STABLE function should be executed once for every different set of
> parameters
Thats not true. Thats not what any of the volatility information (like STABLE,
IMMUTABLE, VOLATILE) does.
See http://www.postgresql.org/docs/current/interactive/xfunc-volatility.html
It *does* change how often a function is executed though. I.e.
SELECT g.i, some_stable_func(1) FROM generate_series(1, 1000) g(i)
will call some_stable_func only once because it can determine all the
parameters beforehand.
Andres
