Re: How can I build OSSP UUID support on Windows to avoid duplicate UUIDs?

On 2013-10-31 08:22:14 -0400, Robert Haas wrote:
> On Wed, Oct 30, 2013 at 5:32 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > "MauMau" <maumau307@gmail.com> writes:
> > Note the lack of enthusiasm for taking on maintainership of the OSSP
> > code.  Pushing it into core would mean that we're buying into that
> > maintainership, hook line and sinker.  I don't think that such a
> > proposal would fly.
> 
> ISTM that the biggest problem is that we don't have a random number
> generator which generates enough bits of randomness to implement
> uuid_generate_v3.  I think relatively few people would cry if we
> didn't support uuid_generate_v1(), and the others all look simple
> enough, provided there's somewhere to get lots of random bits.

Yea, I think restricting ourselves to v3/4/5 is a sensible thing.

> On Linux, it seems like we could get those bits from /dev/urandom,
> though I'm not sure how efficient that would be for the case where
> many UUIDs are being generated at once.  But that wouldn't be very
> portable.  It's tempting to think that we'd need a PRNG that generates
> wider values, for which we might find other application also.  But I'm
> not volunteering to be the one to create such a thing.

We could copy ossp's implementation, it's just 200 lines and seems to
have a compatible license.
util-linux's libuuid is BSD as well and seems to have some windows
support although that's by memory.

Greetings,

Andres Freund

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