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

On Wed, Sep 28, 2022 at 6:17 AM Peter Geoghegan <pg@bowt.ie> wrote:
>
> On Tue, Sep 27, 2022 at 12:15 PM Thomas Munro <thomas.munro@gmail.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.

Regards,

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