Re: Add ALL_CANDIDATES option to EXPLAIN

Robert Haas <robertmhaas@gmail.com> writes:
> I've thought about trying to figure out some way of identifying and
> printing out plans that are "interestingly different" from the chosen
> plan, with the costs they would have had, but I haven't been able to
> come up with a good algorithm.

I wonder how far you'd get by just printing the surviving paths
(that is, something like Anthonin's patch, but without lobotomizing
add_path).  The survivors would have to dominate the cheapest-total
path along one of the other metrics add_path considers, which
seems like a rough approximation of "interestingly different".

            regards, tom lane