On Sunday, October 15, 2023, Victor Dobrovolsky <booby(dot)stager(at)gmail(dot)com>
wrote:
>
> select (case when px is not null then pf = px
> else pf is not distinct from py
> end);
>
>
Every single time this function is called “px is not null” will be
evaluated and then one of the two branches will be evaluated. Nothing the
optimizer does will change that. The planner for the function internals
does not know whether px will or will not be null on any given invocation.
David J.