For accessing previous version, I would do it the same way. :) 1. Can you elaborate on what you mean by that with an example? What do you mean by "accessing" keys?
2. Yeah, that is hard to do with the ability to do point lookups into an RDD, which we dont support yet. You could try embedding the related key in the values of the keys that need it. That is, B will is present in the value of key A. Then put this transformed DStream through updateStateByKey. TD
