Re: [PATCH] Incremental sort

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!

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company