Comment Re:No Cross Database Joins (Score 1) 245
My guess is that he doesn't understand how sequences work, and expects more than just a monotonic counter.
Specifically, I think he missed this line in the documentation:
To avoid blocking concurrent transactions that obtain numbers from the same sequence, a nextval operation is never rolled back; that is, once a value has been fetched it is considered used, even if the transaction that did the nextval later aborts. This means that aborted transactions might leave unused "holes" in the sequence of assigned values.