Re: PG19 FK fast path: OOB write and missed FK checks during batched

On Wed, Aug 19, 2026 at 12:09 AM Noah Misch <noah(at)leadboat(dot)com> wrote:
> On Tue, Aug 18, 2026 at 10:42:14PM +0900, Amit Langote wrote:
> > After considering Peter's report of another bug [1] that is fixed by
> > 0001, I tested both his reproducer and nested firing involving the
> > same constraint.
> >
> > The latter exposed a problem in v1: the cache was still keyed only by
> > constraint OID, so a nested check of the same constraint reused the
> > outer entry and did not register a callback at the nested query depth.
> > In v2, the key is now (constraint OID, query depth), giving each
> > firing level its own entry and callback.
> >
> > 0001 now includes regression tests for both cases. 0002 and 0003 are unchanged.
> >
> > I would like to commit these sometime this week and would appreciate a review.
>
> I won't be able to review this. The list should consider it up for grabs.

Attached is v3, rebased over latest master.

I reorganized the series to separate firing-state restoration (0001),
per-firing-cycle batch and callback scoping that fixes Peter's report
[1] (0002), and per-subtransaction batch tracking as suggested by Noah
(0003). 0003 also folds in the invariant assertion previously sent
separately. The combined code is otherwise unchanged from v2.

[1] https://postgr.es/m/CAH2-Wz%3DD533JbF_ak_Pc8kP0FKse-ju8DnMxtjvY%3D%3DyHsP4xgw%40mail.gmail.com
--
Thanks, Amit Langote