| From: | David Rowley <dgrowleyml(at)gmail(dot)com> |
|---|---|
| To: | Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com> |
| Cc: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Expand applicability of aggregate's sortop optimization |
| Date: | 2024-05-09 01:08:05 |
| Message-ID: | CAApHDvqiqBWCf8E5+KeViH-_p3oNC-5EkYGH7-L3f5w5PPR_pQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, 9 May 2024 at 12:26, David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
> I wonder if we should also consider as an alternative to this to just
> have an aggregate support function, similar to
> SupportRequestOptimizeWindowClause that just nullifies the aggorder /
> aggdistinct fields for Min/Max aggregates on types where there's no
> possible difference in output when calling the transition function on
> rows in a different order.
>
> Would that apply in enough cases for you?
One additional thought is that the above method would also help
eliminate redundant sorting in queries with a GROUP BY clause.
Whereas, the can_minmax_aggs optimisation is not applied in that case.
David
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