On Mon, Oct 17, 2016 at 4:56 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> + node->nreaders < 2)
...
> I see there are small discrepancies in both the codes like I don't see
> the use of single_copy flag, as it is present in gather node.
single_copy doesn't make sense for GatherMerge, because the whole
point is to merge a bunch of individually-sorted output streams into a
single stream. If you have only one stream of tuples, you don't need
to merge anything: you could have just used Gather for that.
It does, however, make sense to merge one worker's output with the
leader's output.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
