Re: BUG #17619: AllocSizeIsValid violation in parallel hash join

On Fri, Sep 30, 2022 at 3:33 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> On Wed, Sep 28, 2022 at 6:17 AM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> >
> > On Tue, Sep 27, 2022 at 12:15 PM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> > > > I believe that Thomas was going to do something like this anyway. I'm
> > > > happy to leave it up to him, but I can pursue this separately if that
> > > > makes sense.
> > >
> > > Why not clobber "lower down" in dsm_create(), as I showed? You don't
> > > have to use the table-of-contents mechanism to use DSM memory.
> >
> > I have no strong feelings either way. That approach might well be better.
> >
> > It might even be useful to do both together. The redundancy probably
> > wouldn't hurt, and might even help in the future (it might not stay
> > redundant forever). We don't necessarily need to worry too much about
> > added cycles for something like this. Just as long as it's not
> > *completely* gratuitous.
>
> +1
>
> I think we can clobber the memory also in dsm_deatch() if the memory
> comes from the pool configured by min_dynamic_shared_memory.

I updated the patch so that it clobbers memory also when dsm_create()
and dsm_detach().

Regards,

--
Masahiko Sawada
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com