Robert Haas <robertmhaas@gmail.com> writes:
> [ lots of numbers ]
> ... I just can't get excited about that. However, I
> find the single-key optimizations much more compelling, for the
> reasons stated above, and feel we ought to include those.
This conclusion seems sound to me, for the reasons you stated and one
more: optimizations for a single sort key are going to be applicable
to a very wide variety of queries, whereas all the other cases are
necessarily less widely applicable.
regards, tom lane