Nanosecond timestamp collisions are common
This is why you should use ids that combine both a time component and a sequence.Eg UUIDv7 has a milliseconds time component and then a field that increments for each event in the same millisecond, and then enough random bits to make collisions between ids generated on different machines astronomically unlikely.Of course there are only so many bits so you might generate too many events in the same time slice so the sequence overflows, and you might actually get collisions between machines, and you are limiting your event generation speed by forcing your cpu to sync on the increment etc.But in practice UUIDv7 works great at scale.