3 ms·

Will the ulid be unique even if it is generated from 2 different machines at the same millisecond?

• tsenart 10y ago
  Yes if you use a good source of entropy. In Go, the easiest and most secure is the `crypto/rand.Reader`. But it's also slow. If you don't need the security properties, an instance of `math/rand.Rand` should suffice. Otherwise, you can implement your own. It's just an io.Reader!
  • Freak_NL 10y ago
    Doesn't that mean that it will usually — but not guaranteed always — be unique? That is, won't there always be a (minute and negligible depending on the intended use) chance of collision?
    • tsenart 10y ago
      Yes, there's always a negligible chance of collision.
• drfuchs 10y ago
  Yes, if your source of entropy is worth its salt.
  • vlowther 10y ago
    That was bad and you should feel bad. :)