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

Hi Amit,

On Thu, Jun 11, 2026 at 5:05 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
>
> On Thu, Jun 11, 2026 at 5:18 PM Junwang Zhao <zhjwpku(at)gmail(dot)com> wrote:
> > I only reviewed and applied patch 0001 on my local machine, and it
> > successfully fixed the crash.
> >
> > One minor comment:
> >
> > + if (fpentry->flushing)
> > + {
> > + ri_FastPathCheck(riinfo, fk_rel, newslot);
> > + return;
> > + }
> >
> > Would it be worth wrapping the condition with unlikely()? It seems
> > this branch is expected to be false in most cases, not a strong
> > opinion though.
>
> Good idea. Will do.
>
> Are you planning to look at 0002?

I just applied 0002 and ran the regression successfully.

I have one trivial comment, subXact abort doesn't NULL the
ri_fastpath_cache, so I think the following comment of
RI_FastPathEntry should be polished accordingly by removing the
`SubXactCallback`.

* ri_FastPathEndBatch(); on abort, ResourceOwner releases the cached
* relations and the XactCallback/SubXactCallback NULL the static cache pointer
* to prevent any subsequent access.

>
> --
> Thanks, Amit Langote

--
Regards
Junwang Zhao