Re: short circuit suggestion in find_hash_columns()

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От Zhihong Yu
Тема Re: short circuit suggestion in find_hash_columns()
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Msg-id CALNJ-vTFRAsyVfDBVTM-_exorQfA9E5iUTBddk9VBa45bHt3hg@mail.gmail.com
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Ответ на Re: short circuit suggestion in find_hash_columns()  (David Rowley <dgrowleyml@gmail.com>)
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On Fri, Jul 9, 2021 at 8:28 AM David Rowley <dgrowleyml@gmail.com> wrote:
On Sat, 10 Jul 2021 at 03:15, Zhihong Yu <zyu@yugabyte.com> wrote:
> I was looking at find_hash_columns() in nodeAgg.c
>
> It seems the first loop tries to determine the max column number needed, along with whether all columns are needed.
>
> The loop can be re-written as shown in the patch.

This runs during ExecInitAgg().  Do you have a test case where you're
seeing any performance gains from this change?

David

Hi,
I made some attempt in varying related test but haven't seen much difference in performance.

Let me spend more time (possibly in off hours) on this.

Cheers

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