On Mon, Aug 9, 2021 at 8:02 AM PG Doc comments form <nore...@postgresql.org> wrote:
> Hello, on page > https://www.postgresql.org/docs/current/row-estimation-examples.html - > there > is a example: > selectivity = (1 - null_frac1) * (1 - null_frac2) * min(1/num_distinct1, > 1/num_distinct2) > = (1 - 0) * (1 - 0) / max(10000, 10000) > = 0.0001 > in the first string " * min" and in the second " / max" > as I understand it isn't correct. > Division is just multiplication by the reciprocal so while the presentation here is inconsistent it is correct. Likewise, the larger a number the smaller its reciprocal, so the change from min to max also works. David J.
