@Raf The framework is highly optimized and the cost should be very small. The performance largely depends on what you do(that is, the custom application logic) in the Flink job. For example, you may define a map function in your job and if the map implementation is very efficient, the performance should be very good. However, if the map implementation is very slow, then it will become the bottleneck for the overall performance. That’s, usually the bottleneck doesn’t comes from the framework, but from the application logic.