On Wed, Apr 26, 2017 at 10:10 AM, Alexander Korotkov
<a.korot...@postgrespro.ru> wrote:
> OK, I get it.  Our qsort is so fast not only on 100% presorted case.
> However, that doesn't change many things in context of incremental sort.

The important point is to make any presorted test case only ~99%
presorted, so as to not give too much credit to the "high risk"
presort check optimization.

The switch to insertion sort that we left in (not the bad one removed
by a3f0b3d -- the insertion sort that actually comes from the B&M
paper) does "legitimately" make sorting faster with presorted cases.

Peter Geoghegan

VMware vCenter Server

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