Re: POC: GROUP BY optimization

From: Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>
To: PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Zhihong Yu <zyu(at)yugabyte(dot)com>, Teodor Sigaev <teodor(at)sigaev(dot)ru>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, David Rowley <dgrowleyml(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>, "a(dot)rybakina" <a(dot)rybakina(at)postgrespro(dot)ru>, Белялов Дамир Наилевич <d(dot)belyalov(at)postgrespro(dot)ru>
Subject: Re: POC: GROUP BY optimization
Date: 2023-07-20 06:37:24
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On 3/10/2022 21:56, Tom Lane wrote:
> Revert "Optimize order of GROUP BY keys".
> This reverts commit db0d67db2401eb6238ccc04c6407a4fd4f985832 and
> several follow-on fixes.
> ...
> Since we're hard up against the release deadline for v15, let's
> revert these changes for now. We can always try again later.

It may be time to restart the project. As a first step, I rebased the
patch on the current master. It wasn't trivial because of some latest
optimizations (a29eab, 1349d27 and 8d83a5d).
Now, Let's repeat the review and rewrite the current path according to
the reasons uttered in the revert commit.

Andrey Lepikhov
Postgres Professional

Attachment Content-Type Size
0001-When-evaluating-a-query-with-a-multi-column-GROUP-BY-20230720.patch text/plain 95.5 KB

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