On May 29, 2019, at 1:36 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> Well, it's all there in the code. I believe the issue is that the
> final estimates are based on the number of rows that will be returned
> from the relation, which is often less, and occasionally more, than
> the total of the rows in the relation. The reason it's often less is
> because there might be a WHERE clause or similar which rules out some
> of the rows. The reason it might be more is because a nested loop
> could return the same rows multiple times.
Yes, indeed. I was confused, and I guess I could've thought about it
about more before posting here. Thank you for answering this
question!
Regards,
Donald Dong