UUID collision is not possible in practice. You can absolutely code in the absolute knowledge that your application will not generate 2 identical UUID's ever. The odds are astronomical. You have bigger concerns.
And yes, every DB backend has solved collision. But as I said, it's useful to be able to generate ID's in code sometimes. This is possible with UUID's and not possible with integers.
UUID is a loosely defined concept. There are many implementations. Some of them have no chance of collision at all, some have an astronomical chance, and some have very real odds that you'll receive a call at 3AM during the new year's celebration.
In the types of systems that need UUIDs there is probably no easy way to check for collisions. The prospect of mystery data corruption with no ability to trace it down frightens the hell out of me.
The only reason that issue was reported is because someone was actually doing the collision checking. That's not going to be the norm in UUID systems. Think about it.
Many shops (I presume, since I work at non-FAANG) have their own version of UUID generation that includes info about the machine/instance it was generated from. I don’t think we’ve formally proved it but I think ours is guaranteed unique in our fleet.
