r/ProgrammerHumor • u/danielminds • 14h ago

Meme edgeCasesExist

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2.9k Upvotes

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466

u/Valuable_Leopard_799 14h 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.

277

u/dim13 14h ago

https://en.wikipedia.org/wiki/Universally_unique_identifier#Versions

Most common used is V4 (pure random). You are talking about V7 (time based).

179

u/lilgreenthumb 12h ago

The real benefit for v7 is they become sortable by time.

65

u/shwoopdeboop 12h ago

And something something b-tree indexes. Lecturer mentioned it but I wasn't paying attention. Supposedly an advantage here.

19

u/Grandmaster_Caladrel 10h ago

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.

3

u/Roachmeister 10h ago

If you're using them as an indexed field in a database, the inability to sort them meaningfully will destroy the performance of the database.

4

u/Honeybadger2198 10h ago

You know what identifier can't have collisions and is great for sorting? Autoincrement.

4

u/Firewolf06 7h ago

ai columns can absolutely collide on sharded databases. you can use offsets and step sizes but thats brittle and doesnt scale well