Michael Meskes <meskes(at)postgreSQL(dot)org> writes:
> I saw that it is a 4 byte integer on my site, but is that guaranteed?
Yes, for now anyway.
Eventually I'd like to see us offering 8-byte OIDs, because a DB that's
been running for a while could wrap around the OID counter and produce
duplicate OIDs :-(. But until support for 8-byte "long long int" is
pretty standard, I don't think we can do it without creating tremendous
portability problems.
regards, tom lane