Atri Sharma <atri.jiit@gmail.com> writes:
> Now, why cannot we take the estimate of all the buckets behind the bucket
> in which our value is present? Will that estimate not give us the fraction
> of tuples that are expected to be before the first matching row?
Uh, no, not unless you assume that the table happens to be perfectly
sorted by the column's value.
regards, tom lane