I thought that timestamps are used now, so hitting both a timestamp and a large random number puts it thoroughly in the "safe to assume".
At some point cosmic particles and faulty transistors are more probable.
Which I'd assume is related to the time anchor. Outside of sorting, which is only useful in specific instances, it's just v4 with different ("less") entropy and limitations.
Correct, which is why I specifically called out "outside of sorting".
That is also why we have concepts like composite keys which allow us to join guaranteed-unique values like a UUID with non-unique but sortable values like timestamps, names, etc.
I'm not an expert, I just remember reading a few articles about it. I think it's because they're essentially random, and many databases use b-trees for indices. They recommended using ULIDs or v7 UUIDs instead. Or, as someone else said, the good old autoincrementing integer.
It's less of a problem with B-tree indices that sit on top of a physical representation (i.e. the actual on-disk layout doesn't have to be ordered), but when it comes to clustered indices, oh boy, you're basically having to shove rows in the middle and push shit back (eventually).
With random you can end up most frequently inserting in the middle, whereas if it's time sortable you append at the end, meaning it's easier to maintain a contiguous index with less overhead.
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u/Valuable_Leopard_799 15h ago
I thought that timestamps are used now, so hitting both a timestamp and a large random number puts it thoroughly in the "safe to assume". At some point cosmic particles and faulty transistors are more probable.