I am pretty new to flink. I have a flink job that has 10 transforms (mostly CoFlatMap with some simple filters and key extractrs as well. I have the config set for 6 slots and default parallelism of 6, but all my stages show paralellism of 1. Is that because there is only one task manager? Some of what I have read suggested separate slots were needed to use multiple threads on a single box? I have read the section on the docs several times and still not totally sure about the execution model.