On May 29, 2019, at 1:36 PM, Robert Haas <robertmh...@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