Robert Haas <robertmhaas@gmail.com> writes:
> But why isn't it just as valuable to have two decimal places for the
> estimate? I theorize that the cases that are really a problem here are
> those where the row count estimate is between 0 and 1 per row, and
> rounding to an integer loses all precision.
Currently, the planner rounds *all* rowcount estimates to integers
(cf. clamp_row_est()). Maybe it'd be appropriate to rethink that,
but it's not just a matter of changing EXPLAIN's print format.
regards, tom lane