On Wed, Sep 20, 2006 at 05:04:00AM -0400, Gregory Stark wrote: > [EMAIL PROTECTED] writes: > > I have the impression I'm not being heard. > > *I* control the MAC address assignment for all of *MY* units. > No, you're missing the point. How does that help *me* avoid collisions with > your UUIDs? UUIDs are supposed to be unique period, not just unique on your > database.
As you already said, they can't be. I don't see how random is better than unique by intent (MAC address). > If all you want is unique number generation in your database then > you can just use sequences and they'll take a lot less space and > perform much better. (16-byte foreign keys throughout the whole > database, *shudder*) I want unique number generation from several separate databases, and I don't like the idea of maintaining complicated SERIAL ranges, or using one of the increment by X, offset Y techniques. Too hard. > The reason to use UUIDs is when you want to have unique identifiers that you > can send outside the database and know they won't conflict with other unique > identifiers generated elsewhere. If you don't control the factors that influence the UUID generation, this is a cross your fingers type of merge. Random numbers might collide. Shared MAC address might collide. Not controlling the time source might collide. Although it will probably work, if I know my domain, if I know what will need to be merged, I can ensure that they can be merged. > Really this whole debate only reinforces the point that there isn't > a single way of doing UUID generation. There are multiple libraries > out there each with pros and cons. It makes more sense to have > multiple pgfoundry UUID generating modules. Exactly. If I lead you to the impression that I want UUIDv1 in core, this was not the intent. What I intend to say is that different people want different implementations, and one of the most useful versions, in my opinion, is difficult to implement portably. Cheers, mark -- [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] __________________________ . . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder |\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ | | | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bind them... http://mark.mielke.cc/ ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend