On Sun, Oct 29, 2023 at 11:56 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Alexander Korotkov <aekorotkov@gmail.com> writes: > I made some beautification of the patch by Andrei. I also removed the > part which changes the target list for estimate_num_groups(). Any > objections to pushing this?
It seems moderately likely that this will break as much as it fixes.
I've not studied the original patch enough to understand why you need to be playing strange games with tree mutation rules, but I suspect that this is band-aiding over some rather fundamentally bad code.
I also have some concerns about this patch. It requires that root->parse remains unchanged during the whole subquery_planner() in order to work, which is an implicit constraint we did not have before.
