From: Gary Wright <gwtmp01@...>
Date: 2007-03-12T09:16:43+09:00
Subject: Re: generate UUID


On Mar 11, 2007, at 6:00 PM, Ryan Davis wrote:
> On Mar 8, 2007, at 5:38 PM, Aaron Smith wrote:
>
> We're using uuidtools at work and it is quite possibly the worst  
> code I've ever come across. Convoluted, obfuscated for the sake of  
> "security" and slow as hell.
>
> % ./blah.rb 100
> ...
> uuidtools-original    0.130000   4.650000   4.780000 (  4.782855)
>
> Yes, 21 uuids per second!
>
> I got a 400x improvement out of it by dropping this into our config/ 
> environment.rb:
>
> def UUID.true_random
>   (1..8).to_a.map { rand(0x10000) }.pack("n8")
> end

I couldn't tell from the message if Ryan or Aaron wrote the
parts I quoted above...

I'm not an expert on UUIDs but I think there is a real
semantic difference between a UUID and a random number
of the same (binary) length.  RFC 4122 has lots of good
information on UUIDs: http://www.ietf.org/rfc/rfc4122.txt

Gary Wright