big-andy-coates commented on a change in pull request #9156: URL: https://github.com/apache/kafka/pull/9156#discussion_r487057805
########## File path: streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java ########## @@ -182,6 +182,8 @@ public String queryableStoreName() { final KTableProcessorSupplier<K, V, V> processorSupplier = new KTableFilter<>(this, predicate, filterNot, queryableStoreName); + processorSupplier.enableSendingOldValues(true); Review comment: `KTableFilter` has a boolean flag internally that also needs to be set if it is to correctly handle old values, (existing code). So if we don't call `enableSendingOldValues` on it, it won't swallow the output when things haven't changed. to put it another way, the `sendOldValues` field of `KTableFilter` is used to both signify that the upstream is sending old values, and to control if the filter should forward old values. I'll split these into two variables. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org