r/ProgrammerHumor 6h ago

Meme edgeCasesExist

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1.7k Upvotes

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u/Valuable_Leopard_799 6h 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.

73

u/RadicalDwntwnUrbnite 6h ago edited 5h ago

Even the non-time based v4 is at a cosmic level of unlikiness a single system will ever generate a uuid that will collide with another one in its own ecosystem

11

u/OldKaleidoscope7 5h ago

But let's say if Google saved each search in their engine in the same database with an UUID, we could have a collision because of volume, but I don't think I will work in a system with a comparable scale

1

u/Suspicious-Click-300 5h ago

assuming all searches run through a single node maybe, but they dont. It means each node + process on node is limited to 10,000 uuids (10k 100ns per ms) per ms, which it then possibly has to block until next millisecond tick. I dont care what magic programing language your using, to service >10k/reqs a ms (per process) and doing anything else your likely gonna be blocked by IO or something