That's useful information Mike. I am a bit curious about what the most
common use cases are for atomic increment/decrement. I'm familiar with
atomic add as a sort of locking mechanism.

They're useful for caching denormalized counts of things. Especially things that change rapidly. Instead of invalidating the counter whenever an event occurs that would incr/decr the counter, you can incr/decr the cached count too.

In the case of Cassandra, they're useful for keeping counts of things in general, since there's no efficient way to perform count operations with Cassandra.

Mike