Andrew Dunstan <andrew@dunslane.net> writes:
> And is it to be unique per machine, or per cluster (since you can have
> many postgresql clusters on one machine).
Actually, there are *lots* of ambiguities there. For instance, if you
pg_dump and reload a cluster do you want the ID to change or stay the
same? How about copying the $PGDATA tree to another server? How about
redirecting the same cluster to listen on a new port number?
regards, tom lane