> why hardcode millisecond scale timestamps in a world where billions of inserts per second are practical on a single server?

> Or if what you want is monotonic distributed timestamps, again, HLC is how you do that properly.

Why not just 64 bit timestamps stapled to a random number? You can be collision proof and monotonic without doing anything fancy.

> this weird scheme vs something that's just the full birthday bound and you never think about it again

But the weird scheme gives you better odds than the birthday bound.