So, I've run into an issue migrating a consumer to use the new 'roundrobin' partition.assignment.strategy. It turns out that several of our consumers use the same group id, but instantiate several different consumer instances (with different topic selectors and thread counts). Often, this is done in a single shared process. It turns out this arrangement is not allowed when using the 'roundrobin' assignment strategy.
I'm curious as to the reason for this restriction? Why is it not also a restriction for the 'range' strategy (which we've been happily using for some time now)? It would seem that as long as you always assign a partition to a consumer instance that is actually selecting it, you should still be able to proceed with the round-robin algorithm (potentially skipping consumers if they can't select the next partition in the list, etc.). Jason
