Date: Sat, 16 May 2020 14:24:31 +0200
From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Teodor Sigaev <teodor@sigaev.ru>,
	Gavin Flower <GavinFlower@archidevsys.co.nz>,
	Andres Freund <andres@anarazel.de>,
	Michael Paquier <michael@paquier.xyz>,
	PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: POC: GROUP BY optimization
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> On Fri, May 15, 2020 at 01:52:20AM +0200, Tomas Vondra wrote:
>
> I wonder if anyone has plans to try again with this optimization in v14
> cycle? The patches no longer apply thanks to the incremental sort patch,
> but I suppose fixing that should not be extremely hard.
>
> The 2020-07 CF is still a couple weeks away, but it'd be good to know if
> there are any plans to revive this. I'm willing to spend some time on
> reviewing / testing this, etc.

Yes, if you believe that this patch has potential, I would love to pick
it up again.

> I've only quickly skimmed the old thread, but IIRC there were two main
> challenges in getting the optimization right:
>
>
> 1) deciding which orderings are interesting / worth additional work
>
> I think we need to consider these orderings, in addition to the one
> specified in GROUP BY:
>
> 1) as specified in ORDER BY (if different from 1)

What is the idea behind considering this ordering?