const mixinafMorphia::IntSequences

(Service) - Creates sequential sequences of Ints as an alternative to using BSON ObjectIds.

It works by creating MongoDB collection (called IntSequences by default) where it stores the last ID for an entity to be used. When a new ID is requested an atomic findAndUpdate operation is run on the collection to both increment and return the relevant document.

By keeping the last IDs stored in the database it ensures the IDs are persisted between system restarts and that multiple clients can generate unique IDs.

While there is an overhead in generating new IDs, Int IDs have the advantage of using less space in indexes, being easier to work with in web applications and they're generally nicer to look at!