I have a RichAsyncFunction that does async queries to an external database. I'm using a Guava cache within the Flink app. I'd like this Guava cache to be serialized with the rest of Flink state in checkpoint/savepoints. However, RichAsyncFunction doesn't support the state functionality at all.
There is one Guava cache for the entire Flink app which might make this scenario simpler. Is there a recommended way to handle this situation? Also, the Flink MapState interface doesn't support check-and-set type functionality and doesn't support lock-free concurrent use like java.util.concurrent.ConcurrentMap and Guava's cache do. I need both of these features for proper concurrent operation. So even if I could use Flink MapState, that doesn't seem like a practical solution.
