On Jan 5, 2011, at 9:01 AM, Tom Lane wrote:
> In practical use I think the odds of a collision are *far* higher than
> you are suggesting, unless the UUID generation is being done with a lot
> more care than is likely if the user takes these sorts of claims at face
> value.
Eh? The user taking such claims at face value has no bearing whatsoever on the quality of the UUID generation algorithm
providedby the OS. So, unless we're talking about users coming up with their own algorithms, it seems reasonable to
assumethat the generation is done with a great deal of care. (And if we are talking about users coming up with their
ownalgorithms, then all bets are off; feel free to assume the worst.) I know that is the case on OS X & Linux. I would
beshocked if it were not the case on Solaris. I would even be surprised if it were not the case on Windows.
The IETF Network Working Group designed UUIDs to ensure that their uniqueness guarantee would be strong enough that no
applicationwould need to worry about duplicates, ever. Claims that collisions are too likely to depend on UUIDs being
uniquereally are claims that the IETF Network Working Group didn't know what it was doing, which I find a bit
ridiculous.
--
Scott Ribe
scott_ribe@elevated-dev.com
http://www.elevated-dev.com/
(303) 722-0567 voice