Hi devs This thread is inspired by FLINK-17015 [1] which meet NEP when SQL guys develop operator based on internal map state.
Unfortunately, we have different behavior of result of internal map state. For HeapMapState, #entries(), #keys(), #values(), and #iterator() would all return null. However, for RocksDBMapState, #entries() would return null, while #keys(), #values(), #iterator() would return empty iterator. I cannot see real benefit for these different behaviors which would confuse internal developers. Moreover, UserFacingMapState would align these behaviors to empty iterator for users. I suggest to align these internal behavior to return empty iterator instead of null. What do you think? [1] https://issues.apache.org/jira/browse/FLINK-17015 Best Yun Tang
