On Tue, Mar 20, 2012 at 1:57 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> That was a long time ago, of course, but I have some vague recollection
> that keeping next-run tuples in the current heap achieves a net savings
> in the total number of comparisons needed to heapify both runs.
Offhand I wonder if this is all because we don't have the O(n) heapify
implemented.
--
greg