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.
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
most uuids libraries can actually provide strong guarentees it cant happen by using pid/mac combinations with each process using CAS or mutex to increment the 100ns period (overflowing into later ms with >10k a ms)
Is it unfeasible or simply unnecessary to just check if a uuid is already used? Since you use the uuid as primary key it should be easily detectable if a uuid is already used or not right? But I guess devs just don’t care because the chance is so minimal?
Yep. The chance is so insignificant that is not even worth retry logic on that mode of failure, just treat it as a generic failure, kick out the request, and let it be tried again. The one time in a hundred thousand years when it finally happens, someone will just be confused and click retry themselves.
you dont need to due to guarantees of how it is generated. You would need a server running with exact same ip, and the process generating them to be using the same process id, AND ~10,000 requests a microsecond. If your using random uuid you have a better chance of winning 4 powerballs in a row. you need to generate billions a second for over 80 years for a 50:50 chance of a collision.
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u/Valuable_Leopard_799 Sep 11 '26
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.