Understand stateful computation

• Overview

  Streaming computation can be either stateless or stateful.

  A stateless program looks at each individual event and creates some output based on that last event;

  A stateful program creates output based on multiple events taken together.

  statefulUsed for definition computation, it is 计算the classification of the function " ".

• References

1. Introduction to Apache Flink by Ellen Friedman, Kostas Tzoumas