Re: Subqueries in Check() -- Still Intentionally Omitted?

On Tue, 2008-09-02 at 19:22 -0400, Tom Lane wrote:
> Jeff Davis <pgsql@j-davis.com> writes:
> > My question is not why don't we allow subqueries in CHECK, my question
> > is why do we allow stable/volatile functions?
>
> Historically we've allowed it, and it's not clear what we'd buy by
> changing that, other than breaking existing applications whose authors
> forgot to mark their functions immutable.  If there were something we
> could usefully do by checking the mutability status of the condition,
> then it would be worth breaking compatibility here...
>

I suppose this means that we're already treating any CHECK constraint as
immutable anyway, e.g. for constraint_exclusion?

Regards,
    Jeff Davis