Re: Parallel vacuum: avoid dangling shared memory pointers

On Wed, Oct 14, 2026 at 7:19 PM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> Hi,
>
> On Wed, Oct 14, 2026 at 1:31 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > > I noticed that two of the parallel vacuum's shared memory pointers
> > > (VacuumSharedCostBalance and VacuumActiveNWorkers) are not reset on
> > > the error path, leaving them dangling, that is, pointing to a shared
> > > memory segment that is already gone, until the next vacuum runs in the
> > > backend or autovacuum worker....
> >
> > +1 to explicitly clear these variables.
> >
> > Given that it doesn't cause any problems today, I think we can apply
> > it only to master.
>
> Other than keeping the version diff small, I don't have a strong
> opinion on back-patching it to PG19, as it doesn't fix a bug. So
> applying it on HEAD looks fine to me.

I've pushed it to master.

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com