Hi Jie, This is by design of Kafka Streams, please read this doc for more details (search for "outputs of the Wordcount application is actually a continuous stream of updates"):
https://kafka.apache.org/0110/documentation/streams/quickstart Note this semantics applies for both windowed and un-windowed tables. Guozhang On Fri, Mar 9, 2018 at 5:36 AM, 杰 杨 <funk...@live.com> wrote: > Hi： > I used TimeWindow for aggregate data in kafka. > > this is code snippet ; > > view.flatMap(new MultipleKeyValueMapper(client) > ).groupByKey(Serialized.with(Serdes.String(), > Serdes.serdeFrom(new CountInfoSerializer(), new > CountInfoDeserializer()))) > .windowedBy(TimeWindows.of(60000)).reduce(new > Reducer<CountInfo>() { > @Override > public CountInfo apply(CountInfo value1, CountInfo value2) { > return new CountInfo(value1.start + value2.start, > value1.active + value2.active, value1.fresh + value2.fresh); > } > }) .toStream(new KeyValueMapper<Windowed<String>, CountInfo, > String>() { > @Override > public String apply(Windowed<String> key, CountInfo value) { > return key.key(); > } > }).print(Printed.toSysOut()); > > KafkaStreams streams = new KafkaStreams(builder.build(), > KStreamReducer.getConf()); > streams.start(); > > and I test 30000 data in kafka . > and I print key value . > > > [KTABLE-TOSTREAM-0000000007]: [99999_99999_2018-03-09_hour_ > 21@1520601300000/1520601360000], CountInfo{start=12179, active=12179, > fresh=12179} > [KTABLE-TOSTREAM-0000000007]: > [99999_99999_2018-03-09@1520601300000/1520601360000], > CountInfo{start=12179, active=12179, fresh=12179} > [KTABLE-TOSTREAM-0000000007]: [99999_99999_2018-03-09_hour_ > 21@1520601300000/1520601360000], CountInfo{start=30000, active=30000, > fresh=30000} > [KTABLE-TOSTREAM-0000000007]: > [99999_99999_2018-03-09@1520601300000/1520601360000], > CountInfo{start=30000, active=30000, fresh=30000} > why in one window duration will be print two result but not one result ? > > ________________________________ > funk...@live.com > -- -- Guozhang
