RE: Add enable_groupagg GUC parameter to control GroupAggregate usage

Hi Richard,

>> Attached is a rebased patch to make cfbot work again.
>
>I intend to push this patch soon.  That way newly added test cases can
>start using enable_groupagg directly.  Otherwise we'll have to keep
>rebasing it to convert any new tests that use enable_sort to force
>hashed grouping.  Any thoughts?

I'm in favor of committing this.
Before you do, I'd like to clarify one point regarding the commit message. 
Would it make sense to list both of us as authors?

The reason I ask is that you made substantial changes to the patch, 
including handling additional plan nodes such as SetOp and adding regression 
tests. Given those contributions, I wondered whether it would be more 
appropriate for both of us to be listed as authors. (I've seen past commits that 
included two Author: lines.)
I'm happy to leave that decision to you.

By the way, I re-ran the test query from the initial email in this thread.
The execution times were:

  Default: 25,791.642 ms
  SET enable_groupagg TO off;: 1,006.839 ms

This again confirmed an approximately 25x speedup.

Of course, the actual benefit depends on the specific query, but I believe 
this parameter will allow users to improve query performance in more situations.

Regards,
Tatsuro Yamada

> -----Original Message-----
> From: Richard Guo <guofenglinux@gmail.com>
> Sent: Tuesday, July 7, 2026 3:53 PM
> To: Tatsuro Yamada（山田達朗） <tatsuro.yamada@ntt.com>
> Cc: Tatsuro Yamada <yamatattsu@gmail.com>; David Rowley
> <dgrowleyml@gmail.com>; Ashutosh Bapat
> <ashutosh.bapat.oss@gmail.com>; pgsql-hackers@lists.postgresql.org
> Subject: Re: Add enable_groupagg GUC parameter to control GroupAggregate
> usage
> 
> On Tue, Jul 7, 2026 at 3:47 PM Richard Guo <guofenglinux@gmail.com>
> wrote:
> > Attached is a rebased patch to make cfbot work again.
> 
> I intend to push this patch soon.  That way newly added test cases can
> start using enable_groupagg directly.  Otherwise we'll have to keep
> rebasing it to convert any new tests that use enable_sort to force
> hashed grouping.  Any thoughts?
> 
> - Richard