Re: Buffers from parallel workers not accumulated to upper nodes with gather merge

On Thu, Jul 23, 2020 at 3:59 PM Jehan-Guillaume de Rorthais
<jgdr(at)dalibo(dot)com> wrote:
>
> On Thu, 23 Jul 2020 15:44:16 +0530
> Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> > On Tue, Jul 21, 2020 at 9:05 PM Jehan-Guillaume de Rorthais
> > <jgdr(at)dalibo(dot)com> wrote:
> > >
> > > On Mon, 20 Jul 2020 15:29:00 +0530
> > > Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > >
> > > > BTW, can you please test if the problem exist in back-branches, and does
> > > > your change fix it there as well?
> > >
> > > Gather Merge appears in v10, but I haven't been able to produce a plan
> > > using it.
> >
> > I am able to do it for v10. I think you can try by "set
> > enable_hashagg = off;" and following all other steps mentioned in your
> > email?
>
> Indeed. I confirm it produces the same result. I've been able to successfully
> test to proposed fix.
>

Cool.

> > Attached, please find the patch for v10 with a modified commit
> > message. I will do it for other versions as well if you are fine with
> > it?
>
> I'm not an english-native writer, but I would rephrase this:
>
> We can do a similar thing for Gather Merge as well but it seems the better
> to account for stats during nodes shutdown after completing the execution.
>

Fair enough. I will adopt your suggestion before commit. I'll wait
for a day or so to see if anyone has more comments.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com