I wrote:
>> Attached is a version that addresses today's concerns, and also finishes
>> filling in the loose ends I'd left before, such as documentation and
>> outfuncs.c support. I think this is in a committable state now, though
>> I plan to read through the whole thing again.
The extra read-through located some minor bugs, mainly places where I'd
forgotten to ensure that Path cost info was transposed into the generated
Plan. That would only have the cosmetic effect that EXPLAIN would print
zeroes for estimated costs, and since we only use EXPLAIN COSTS OFF in
the regression tests, no test failures ensued :-(.
I've pushed it now; we'll soon see if the buildfarm finds any problems.
regards, tom lane