Re: Tom Lane
> > Extending the idea, perhaps the check could be moved to run-time and
> > recursively check that only immutable functions are called, including
> > user-defined immutable functions?
>
> I don't think I'd trust that. UDFs can claim to be immutable but
> be lying about it.
That's why I said "recursively". Then truly immutable user-defined
functions could still be used.
But practically, people will probably want to select from other tables
anyway (I've already had to tell a customer that virtual columns do
not allow that), so the use-case for user immutable functions is
probably very thin.
Christoph