Thread: immutable function calling stable function

Hi,

shouldn't it be illegal for an immutable function to call a stable one?

-- 
Markus Bertheau <twanger@bluetwanger.de>

Markus Bertheau <twanger@bluetwanger.de> writes:
> shouldn't it be illegal for an immutable function to call a stable one?

No, because that's the standard hack for getting around it when you wish
to call a stable function in what you know to be a "safe" way.  If you
look in the archives you'll find cases where creating an immutable
wrapper function was the recommended solution to performance problems.
        regards, tom lane

On Wed, 21 Jul 2004, Markus Bertheau wrote:

> shouldn't it be illegal for an immutable function to call a stable one?

It's expected that the function's creator is responsible for properly
marking its stability. This allows some flexibility when you know more
than the system does (for example, a stable function that isn't immutable
because of its use of a GUC variable being called from a function that
sets said variable).