Re: [HACKERS] [PATCH] Incremental sort

On Wed, Apr 26, 2017 at 11:39 AM, Alexander Korotkov
<a.korotkov@postgrespro.ru> wrote:
> But I'd like to make incremental sort not slower than quicksort in case of
> presorted data.  New idea about it comes to my mind.  Since cause of
> incremental sort slowness in this case is too frequent reset of tuplesort,
> then what if we would artificially put data in larger groups.  Attached
> revision of patch implements this: it doesn't stop to accumulate tuples to
> tuplesort until we have MIN_GROUP_SIZE tuples.
>
> Now, incremental sort is not slower than quicksort.  And this seems to be
> cool.
> However, in the LIMIT case we will pay the price of fetching some extra
> tuples from outer node.  But, that doesn't seem to hurt us too much.
>
> Any thoughts?

Nice idea.