Re: [BUG] Planner bug causes incorrect query results in PG14 and PG15

g l <orangegrove(at)live(dot)com> writes:
> This bug affects only versions below pg 16. Ver 16 has a fundamental infrasturctural update, eliminating the root cause of the bug. But for versions below 16, they lack the mechanism intrduced in ver 16, so we have to take another approach to handle the bug.

TBH, I'm unexcited about doing anything at all here. v14 is out of
support as of yesterday, so it's not going to get patched in any case.
As for v15, I question the value of attempting to fix it. Any patch
that we'd be willing to commit would necessarily be localized and
conservative, which means that along with fixing broken plans it would
probably de-optimize some plans that weren't broken. Meanwhile there
have been very few complaints about incorrect plans (though I concede
that people may just not realize they are getting wrong answers).
So it's entirely possible that a fix would hurt more people than
it helps.

I think the most practical solution is to leave v15 alone, and
tell any complainers that the fix is to update to v16 or later.
It's time for them to start thinking about doing that anyway.

regards, tom lane