Fw: Re: Bitmap scan seem like such a strange choice when "limit 1"

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, September 7, 2020 9:04 AM, Klaudie Willis <Klaudie(dot)Willis(at)protonmail(dot)com> wrote:

> Maybe the right way to improve this is to bypass add_paths_to_append_rel
> entirely when there's exactly one surviving child rel, and make it
> just use all the surviving paths for that child.
> regards, tom lane

Does this classify as a bug, or is it "by design"? Should I submit one for PG13beta3? To me, this seems like quite a straight forward case. Big database partitioned, two key lookups, both indexed where one key isolates a partition, and with a limit constraint. Yet it chooses a plan that is 1000x slower than the optimal plan.

K