I think you are trying collecting data from multple kafka server. This means each server has a dedicate foreign table on a dedicate foreign server. Parallel execution doesn't fit in that case since it works on single base relation (or a table). Parallel append/merge append look a bit different but actually is the same in the sense that one base relation is scanned on multiple workers. Even if you are trying to fetch from one kafka stream on multiple workers, I think the fdw driver doesn't support parallel scanning anyway.
Well my idea was to to scan multiple partitions from a single kafka
server / topic in parallel.
I’ll will look into your suggestion to set up partial paths
