Re: Is there value in having optimizer stats for joins/foreignkeys?

Alexandra Wang <alexandra.wang.oss@gmail.com>

From: Alexandra Wang <alexandra.wang.oss@gmail.com>

To: pgsql-hackers@lists.postgresql.org

Cc: Tomas Vondra <tomas@vondra.me>, Andrei Lepikhov <lepihov@gmail.com>, Corey Huinker <corey.huinker@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, hs@cybertec.at, Jeff Davis <pgsql@j-davis.com>

Date: 2026-04-29T13:08:58Z

Lists: pgsql-hackers

Attachments

v2-0001-Add-join-MCV-statistics-for-selectivity-estimatio.patch (application/octet-stream) patch v2-0001

On Tue, Apr 28, 2026 at 10:59 PM Alexandra Wang <
alexandra.wang.oss@gmail.com> wrote:
> I've attached the v1 patch and am looking for reviews.

Sorry for the CI breakage!

The Assert(ndims >= 2) in multi_sort_init() failed for join stats that
have a single filter column. Attached v2 that fixed it (relaxed to
ndims >= 1, plus a shadowed variable warning from GCC).

The pg_upgrade failure is expected due to the new catalog columns.
I will post a fix soon.

Best,
Alex