Hello all, I have been looking into different StreamPartitioner<T> implementations of Flink, and I noticed they come with an implementation of selectChannel(), as defined in the ChannelSelector<T> interface. In order to understand better the actions of a StreamPartitioner during execution, I set up Flink on a single server with one TaskManager that had 16 slots. Then, I submitted a job, with a HashPartitioner (through a keyBy() transformation), and remote debugged it to see when the HashPartitioner's selectChannel() method is called. Unfortunately, the breakpoint is never reached and the job completes successfully. Is the previous behavior normal? If yes, why is the breakpoint never reached? Does it have to do with running the job in an environment with local slots? Also, what determines the number of channels when a job is executed? Does it have to do with the number of available slots in the downstream operation of the partitioner?
Thank you for your time and I appreciate any answers/comments/indications. Kind Regards. Nikos R. Katsipoulakis Department of Computer Science, University of Pittsburgh
