Re: Add enable_groupagg GUC parameter to control GroupAggregate usage

Hi Ashtosh and hackers,


> >Some of those instances are for plan stability, all of which need not be
> replicated. But some of them explicitly test sort based grouping. For rest
> of them hash based plan seems to be the best one, so explicit
> enable_groupagg = false is not needed. We will need some test to test the
> switch though.
>
> Thanks for your advice. I'll create a regression test and send a new patch
> to -hackers in my next email.
>

I created a regression test to check the enable_groupagg parameter in
the new patch.
To ensure plan stability, I disabled parallel query by setting the
max_parallel_*
parameters to 0.

Any feedback is welcome.
Please see the attached file.

Thanks,
Tatsuro Yamada