Re: Add proper planner support for ORDER BY / DISTINCT aggregates

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От Richard Guo
Тема Re: Add proper planner support for ORDER BY / DISTINCT aggregates
Дата
Msg-id CAMbWs4_+5cP+8xjiAc=hds935ZiiG6oepPDeVNovWhQ66DARJw@mail.gmail.com
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Ответ на Re: Add proper planner support for ORDER BY / DISTINCT aggregates  (David Rowley <dgrowleyml@gmail.com>)
Ответы Re: Add proper planner support for ORDER BY / DISTINCT aggregates
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On Tue, Nov 8, 2022 at 9:31 AM David Rowley <dgrowleyml@gmail.com> wrote:
I've been playing around with the attached patch which does:

1. Adjusts add_paths_to_grouping_rel so that we don't add a Sort path
when we can add an Incremental Sort path instead. This removes quite a
few redundant lines of code.
 
For unsorted paths, the original logic here is to explicitly add a Sort
path only for the cheapest-total path.  This patch changes that and may
add a Sort path for other paths besides the cheapest-total path.  I
think this may introduce in some unnecessary path candidates.

I think it's good that this patch removes redundant codes.  ISTM we can
do the same when we try to finalize the partially aggregated paths from
partially_grouped_rel.

Thanks
Richard

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