Re: Explain buffers wrong counter with parallel plans

> On Jul 28, 2018, at 2:14 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Fri, Jul 27, 2018 at 11:12 PM, Jonathan S. Katz
> <jonathan(dot)katz(at)excoventures(dot)com> wrote:
>>
>>> On Jul 27, 2018, at 8:31 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>>>
>>>
>>> Yeah, that would be better. Today, I have tried the patch on both
>>> Head and PG11 and I am getting same and correct results.
>>
>> I have applied the the patch to PG11beta2 and tested.
>>
>
> I think we should backpatch this till 9.6 where the parallel query was
> introduced. Note, that for HEAD and 11, the patch is same. For PG10,
> the patch code is same, but because surrounding code is different, the
> same patch didn't apply. For 9.6, we don't need to collect stats in
> ExecShutdownNode. I have tested it in all the back branches and it
> works fine.

The logic on backpatching seems sounds. I confirmed my tests of the respective
patches against 9.6.9 and 10.4. I'll defer to someone else for comments on the
code, but from my read it appears to be a consistent approach for each version.

Jonathan