I'm experimenting with the Kafka Streams preview and understand that joins can only happen between KStreams and/or KTables that are co-partitioned. This is a reasonable limitation necessary to support large streams.
What if I have a small topic, though, that I'd like to be able to join based on values in a stream's messages rather than the partition key? Could there be a concept of a fully replicated KTable where every thread in my Kafka Streams application would read a full copy into memory to be available for joins without the restriction on shared keys? I could probably achieve the effect I want by implementing a consumer in a separate thread to read the topic into RocksDB. I would then do lookups from that separate RocksDB instance in "map" operations within my Kafka Streams application. Is there an easier alternative that I'm missing? It would nice to have a standard mechanism for maintaining small topics like these and making them available for joins without key restrictions.
