2 questions about volatile attribute of pg_proc.

Hi:

We know volatile is very harmful for optimizers and it is the default
value (and safest value) if the user doesn't provide that. Asking user
to set the value is not a good experience, is it possible to auto-generate
the value for it rather than use the volatile directly for user defined
function. I
think it should be possible, we just need to scan the PlpgSQL_stmt to see
if there
is a volatile function?

The second question "It is v for “volatile” functions, whose results might
change at any time.
(Use v also for functions with side-effects, so that calls to them cannot
get optimized away.)"
I think they are different semantics. One of the results is volatile
functions can't be removed
by remove_unused_subquery_output even if it doesn't have side effects. for
example:
select b from (select an_expensive_random(), b from t); Is it by design
on purpose?

--
Best Regards
Andy Fan (https://www.aliyun.com/)