| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Removing Functionally Dependent GROUP BY Columns |
| Date: | 2015-12-02 23:50:04 |
| Message-ID: | CA+TgmoYwtr5WyGTG6GVE_1d4GA7UvtvbO0GhoTBVVsrCKnZQ7g@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Nov 30, 2015 at 11:00 PM, David Rowley
<david(dot)rowley(at)2ndquadrant(dot)com> wrote:
> There are in fact also two queries in TPC-H (Q10 and Q18) which are written
> to include all of the non-aggregated column in the GROUP BY list. During a
> recent test I witnessed a 50% gain in performance in Q10 by removing the
> unneeded columns from the GROUP BY clause.
Wow, that's pretty impressive. +1 for trying to do something about this.
(Full disclosure: I have not read your patch.)
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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