Jeremy Drake <pgsql@jdrake.com> writes:
> I must jump in with my amusement at this whole conversation. I just
> looked up the standard (http://www.ietf.org/rfc/rfc4122.txt) and it
> includes this abstract:
> A UUID is 128 bits long, and can guarantee
> uniqueness across space and time.
The only meaningful word in that claim is "can". Which boils down to
"if everybody always follows best practices and no failures ever occur,
maybe they're really unique". We already know that two of the more
critical assumptions embedded in those best practices (unique MAC
addresses and always-correct system clocks) are seriously flawed in
the real world.
To see just how much of the kool-aid that RFC's authors have been
drinking, note that their "sample implementation" in Appendix A
implements the unique node identifier as ... a random number.
So much for guaranteed uniqueness.
regards, tom lane