2020-12-02

Application state is a first-class citizen in Flink

Multiple State Primitives
Pluggable State Backends
Exactly-once state consistency
Large State asynchronous and incremental checkpoint algorithm
Scalable Applications

A ProcessFunction can arbitrarily modify its state and register timers that will trigger a callback function in the future. Hence, ProcessFunctions can implement complex per-event business logic as required for many stateful event-driven applications.