Hi, all. I created the JIRA https://issues.apache.org/jira/browse/FLINK-4856 to propose adding MapStates into Flink.
MapStates are very useful in our daily jobs. For example, when implementing DistinctCount, we store the values into a MapState and the result of each group(key) is exactly the number of entries in the MapState. In my opinion, the methods provided by the MapState may include: * void put(K key, V value) * V get(K key) * Iterable<K> keys() * Iterable<V> values() * Iterator<Tuple2<K, V>> iterator() Do you have any comments? Any is appreciated. Xiaogang
