Re: [PATCH] Incremental sort

On April 3, 2017 12:03:56 PM PDT, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
>On Mon, Apr 3, 2017 at 9:34 PM, Andres Freund <andres(at)anarazel(dot)de>
>wrote:
>
>> On 2017-03-29 00:17:02 +0300, Alexander Korotkov wrote:
>> > On Tue, Mar 28, 2017 at 5:27 PM, David Steele <david(at)pgmasters(dot)net>
>> wrote:
>> > > On 3/20/17 10:19 AM, Heikki Linnakangas wrote:
>> > >
>> > >> On 03/20/2017 11:33 AM, Alexander Korotkov wrote:
>> > >>
>> > >>> Please, find rebased patch in the attachment.
>> > >>>
>> > >>
>> > >> I had a quick look at this.
>> > >>
>> > >
>> > > <...>
>> > >
>> > > According to 'perf', 85% of the CPU time is spent in
>ExecCopySlot(). To
>> > >> alleviate that, it might be worthwhile to add a special case for
>when
>> > >> the group contains exactly one group, and not put the tuple to
>the
>> > >> tuplesort in that case. Or if we cannot ensure that the
>Incremental
>> Sort
>> > >> is actually faster, the cost model should probably be smarter,
>to
>> avoid
>> > >> picking an incremental sort when it's not a win.
>> > >>
>> > >
>> > > This thread has been idle for over a week. Please respond with a
>new
>> > > patch by 2017-03-30 00:00 AoE (UTC-12) or this submission will be
>> marked
>> > > "Returned with Feedback".
>>
>> > Thank you for reminder!
>>
>> I've just done so. Please resubmit once updated, it's a cool
>feature.
>>
>
>Thank you!
>I already sent version of patch after David's reminder.
>Please find rebased patch in the attachment.

Cool. I think that's still a bit late for v10?

Andres
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