Re: unstable query plan on pg 16,17,18

On 23 Feb 2026, at 21:25, Andrei Lepikhov <lepihov(at)gmail(dot)com> wrote:
> Thanks. But I meant your 'good' plan built by the PG14. I think a new feature invented later has added some problems.
>
> Current conjecture is the following. As I see, the main problem is with Right Hash Join:
> -> Hash Right Join (cost=210369.25..210370.30 rows=8 width=99)
> Its inner side (Hash table) is rebuilt multiple times (around 1k) due to an external parameter (gauf_1.id) in the subtree. It looks like a disaster, and before I thought we don't build hash tables over parameterised query trees at all.
>
> So, let me discover a little more, but your PG14 explain could add more details here.

Sorry, I misunderstood that.
here is the pg14.4 explain

https://explain.depesz.com/s/eb32

Regards,
Attila