Re: v16 regression - wrong query results with LEFT JOINs + join removal

On Thu, May 11, 2023 at 9:57 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > While merging commits from c9f7f926484d69e2806e35343af7e472fadfede7
> > through 3db72ebcbe20debc6552500ee9ccb4b2007f12f8 into a fork, my
> > colleague Rushabh Lathia and I noticed that the merge caused certain
> > queries to return wrong answers.
>
> I believe this is a variant of the existing open issue about
> the outer-join-Vars stuff:
>
> https://www.postgresql.org/message-id/flat/0b819232-4b50-f245-1c7d-c8c61bf41827%40postgrespro.ru

Ouch, so we've had a known queries-returning-wrong-answers bug for
more than two months. That's not great. I'll try to find time today to
check whether the patches on that thread resolve this issue.

> I've been incredibly distracted by $real-life over the past few
> weeks, but am hoping to get the outer-join-Vars issues resolved
> in the next day or two.

Thanks. Hope the real life distractions are nothing too awful, but
best wishes either way.

--
Robert Haas
EDB: http://www.enterprisedb.com