Interesting problem about uuid1

[alex23]

On Nov 21, 5:33 pm, sword <john... at gmail.com> wrote:
> My colleague asks me an interesting problem about uuid library in
> python. In multicore system with multiprocessing, is it possible to
> get the duplicated uuid with uuid1?
>
> I just check the RFC 4122, and I can't find anything about multicore
> environment. Python's uuid1 method generates the uuid with time stamp,
> mac address, and algorithm to gen random numbers. So, I think it's
> possible to get the duplicate uuid1 at the same time.
>
> What about you? Hope for your reply

Check the library documentation: http://docs.python.org/library/uuid.html

uuid.uuid1([node[, clock_seq]])
Generate a UUID from a host ID, sequence number, and the current time.
If node is not given, getnode() is used to obtain the hardware
address. If clock_seq is given, it is used as the sequence number;
otherwise a random 14-bit sequence number is chosen.

Each process would have to not only execute at the exact same time, it
would have to generate the same 14-bit random sequence. And if you're
really concerned, try specifying a different clock_seq for each core.