Vesper Sync Diary #8 part three - Unique IDs and Hashing
In More about Unique IDs I decided to use a client-generated UUID for notes.
The thing about 64-bit values is that they’re much easier to handle than 128-bit values. For example, the Core Data modeler has Integer 16, Integer 32, and Integer 64, but no Integer 128.
So the idea is this: when I need a 64-bit ID, I create a new UUID and then pass it to CityHash64().
There is no practical reason to worry about collisions — especially given that an ID has to be unique per-account, not system-wide.
Nevertheless, a test to put my mind at ease would be a good idea. I’ll write a little app that generates a few million of these from UUIDs and make sure I don’t see collisions.