From John :
I also meant to talk with you about the change to allow querying recovering stores. I think you might have already talked with Matthias a little about this in the scope of KIP-216, but it's probably not ok to just change the default from only allowing query while running, since there are actually people depending on full-consistency queries for correctness right now.
What we can do is add an overload KafkaStreams.store(name, QueriableStoreType, QueriableStoreOptions), with one option: queryStaleState(true/false) (your preference on the name, I just made that up right now). The default would be false, and KSQL would set it to true. While false, it would not allow querying recovering stores OR standbys. This basically allows a single switch to preserve existing behavior.