On Thu, Apr 27, 2017 at 5:06 PM, Robert Haas <robertmh...@gmail.com> wrote:
> On Wed, Apr 26, 2017 at 11:39 AM, Alexander Korotkov > <a.korot...@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. Cool. Than I'm going to make a set of synthetic performance tests in order to ensure that there is no regression. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
