On Fri, 3 Oct 2025 at 02:55, Mingli Zhang <zmlpostgres@gmail.com> wrote:
> It seems that the optimization for `UNION ALL` is already implemented in the patch: it removes empty sub-paths and
preservesthe remaining ones.
> Should we add a test case to formally validate this behavior like Union cases?
If I were to do that, I'd have to come up with something that's
flatten_simple_union_all() proof. Maybe something like varying types
in the targetlist. I think it's probably not really worthwhile since
it's not testing any new code that is not already being tested by the
tests that I did add.
David
