Robert Haas <robertmhaas@gmail.com> writes:
> Perhaps this is a silly question, but I don't particularly see what's
> wrong with:
> 3. Do nothing.
Well, the fundamental problem is that the RTE is a lousy place to keep
rowcount estimates. That breaks assorted desirable properties like
querytrees being readonly to planning/execution (not that we don't
end up copying them anyway, but up to now that's been because of bad
implementation not because the representation was broken by design).
I agree that it's probably not so badly broken that we have to fix it
in time for v10, but this is not where we want to be in the long run.
regards, tom lane