Re: When IMMUTABLE is not.

Yura Sokolov <y.sokolov@postgrespro.ru> writes:
> I found, than declaration of function as IMMUTABLE/STABLE is not enough to be sure
> function doesn't manipulate data.

Of course not.  It is the user's responsibility to mark functions
properly.  Trying to enforce that completely is a fool's errand;
you soon get into trying to solve the halting problem.

I don't like anything about the proposed patch.  It's necessarily
only a partial solution, and it probably breaks cases that are
perfectly safe in context.

            regards, tom lane