Re: Patch for UUID datatype (beta)

On Mon, 2006-09-18 at 09:21 +0200, Andreas Pflug wrote:
> Gevik Babakhani wrote:
> > - new_guid() function is supported. This function is based on V4 random
> > uuid value. It generated 16 random bytes with uuid 'variant' and
> > 'version'. It is not guaranteed to produce unique values
>
> Isn't guaranteed uniqueness the very attribute that's expected? AFAIK
> there's a commonly accepted algorithm providing this.
>

uniqueness is never a guaranteed. that is according to the RFC docs.
However the new_guid() generates a random value in the range of 256^256.
The random value is again based on the PG's randomizer which is a very
good one.

uniqueness is never a guaranteed in the sense that there is a tiny
chance someone of the other side of the planet might generate the same
guid. Or if you set your PC's clock back to the past (1981) you have a
tiny chance to generate a same guid twice.

I am running a test that is going on for the past two days, in has
generated over 14 million guids with new_guid() and yet no
duplicates :)

Regards,
Gevik


> Regards,
> Andreas
>
>