CODEWITHSUNDEEP
pythonuuid
bieboebap
bieboebap

Reputation: 310

Should an application check for UUID v4 duplicated?

I work in my app with a database. This database stores data with a randomly generated ID of the type UUID v4. Now I'm wondering, how common is it for a big (let's be optimistic :D ) app with many users to have a duplicate ID? The ID is the primary key in the SQL database so it could only crash one API call. Is it a clean practice to check if the UUID exists (and thus catch a possible crash in the backend) or is it redundant as it's very unlikely to happen?

Especially considering:

EDIT:

Based on the comments it seems unnecessary to check for duplicates. Thanks!

Upvotes: 3

Views: 1657

Answers (1)

mozway
mozway

Reputation: 260630

This shouldn't be a problem in practice due to the very low probability of collisions.

See the Wikipedia article on UUID4 collision

For example, the number of random version-4 UUIDs which need to be generated in order to have a 50% probability of at least one collision is 2.71 quintillion

This number is equivalent to generating 1 billion UUIDs per second for about 85 years. A file containing this many UUIDs, at 16 bytes per UUID, would be about 45 exabytes.

NB. UUID1 and UUID2 have a time component which make it impossible to have collisions if the UUIDs are generated at a reasonable enough frequency.

Upvotes: 3

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