Network Buffer Exhaustion
warningDepleted network buffers block data shuffling between operators, causing backpressure and throughput collapse in jobs with high shuffle volume.
Monitor flink_taskmanager_status_shuffle_netty_availablememorysegments approaching zero while flink_taskmanager_status_shuffle_netty_memorysegments remains constant. When buffer pool usage (flink_task_shuffle_netty_input_buffer_inpoolusage or flink_task_shuffle_netty_output_buffer_outpoolusage) approaches 100%, combined with increasing queue lengths (flink_task_shuffle_netty_input_buffer_inputqueuelength, flink_task_shuffle_netty_output_buffer_outputqueuelength), network buffers are exhausted.
Increase network buffer allocation in TaskManager memory configuration. Reduce shuffle operations by optimizing operator chaining where possible. For jobs with heavy keyBy operations, verify parallelism is appropriate to avoid excessive data redistribution. Check for data skew causing uneven buffer usage across subtasks.