From: | Andres Freund <andres(at)anarazel(dot)de> |
---|---|
To: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
Cc: | David Steele <david(at)pgmasters(dot)net>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [PATCH] Incremental sort |
Date: | 2017-04-03 18:34:38 |
Message-ID: | 20170403183438.5matptjo6xhghpnu@alap3.anarazel.de |
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Lists: | pgsql-hackers |
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:
>
> > Hi Alexander,
> >
> > 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.
- Andres
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