@zoltan.zvara looks like you found my easter egg!
The issue with the retries above looks like a bug in the DCP implementation - we are currently working on a replacement for it and its coming along pretty well… It is under heavy development and not complete, but if you are curious you can star/track the progress on this repo: GitHub - couchbase/java-dcp-client: Couchbase Java DCP Client
Once it is in a stable and supportable condition we’ll integrate it transparently with spark, that will solve the current issues with spark streaming in general 
p.s.: the reason why the dcp stuff doesn’t look polished is: it isn’t 
… it has always been experimental and we now have enough data together to build something substantial that will help us get to the point of a stable and supportable streaming system into spark, kafka and other consumers. Stay tuned!