Proper way to assign watermark with DateStreamSource<List> using Flink





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I have a continuing JSONArray data produced to Kafka topic,and I wanna process records with EventTime characteristic.In order to reach this goal,I have to assign watermark to each record which contained in the JSONArray.



I didn't find a convenience way to achieve this goal.My solution is consuming data from DataStreamSource> ,then iterate List and collect Object to downstream with an anonymous ProcessFunction,finally assign watermark to the this downstream.



The major code shows below:




DataStreamSource<List<MockData>> listDataStreamSource = KafkaSource.genStream(env);
SingleOutputStreamOperator<MockData> convertToPojo = listDataStreamSource
.process(new ProcessFunction<List<MockData>, MockData>() {
@Override
public void processElement(List<MockData> value, Context ctx, Collector<MockData> out)
throws Exception {
value.forEach(mockData -> out.collect(mockData));
}
});
convertToPojo.assignTimestampsAndWatermarks(
new BoundedOutOfOrdernessTimestampExtractor<MockData>(Time.seconds(5)) {
@Override
public long extractTimestamp(MockData element) {
return element.getTimestamp();
}
});
SingleOutputStreamOperator<Tuple2<String, Long>> countStream = convertToPojo
.keyBy("country").window(
SlidingEventTimeWindows.of(Time.seconds(10), Time.seconds(10)))
.process(
new FlinkEventTimeCountFunction()).name("count elements");



The code seems all right without doubt,running without error as well.But ProcessWindowFunction never triggered.I tracked the Flink source code,find EventTimeTrigger never returns TriggerResult.FIRE,causing by TriggerContext.getCurrentWatermark returns Long.MIN_VALUE all the time.



What's the proper way to process List in eventtime?Any suggestion will be appreciated.










share|improve this question





























    0















    I have a continuing JSONArray data produced to Kafka topic,and I wanna process records with EventTime characteristic.In order to reach this goal,I have to assign watermark to each record which contained in the JSONArray.



    I didn't find a convenience way to achieve this goal.My solution is consuming data from DataStreamSource> ,then iterate List and collect Object to downstream with an anonymous ProcessFunction,finally assign watermark to the this downstream.



    The major code shows below:




    DataStreamSource<List<MockData>> listDataStreamSource = KafkaSource.genStream(env);
    SingleOutputStreamOperator<MockData> convertToPojo = listDataStreamSource
    .process(new ProcessFunction<List<MockData>, MockData>() {
    @Override
    public void processElement(List<MockData> value, Context ctx, Collector<MockData> out)
    throws Exception {
    value.forEach(mockData -> out.collect(mockData));
    }
    });
    convertToPojo.assignTimestampsAndWatermarks(
    new BoundedOutOfOrdernessTimestampExtractor<MockData>(Time.seconds(5)) {
    @Override
    public long extractTimestamp(MockData element) {
    return element.getTimestamp();
    }
    });
    SingleOutputStreamOperator<Tuple2<String, Long>> countStream = convertToPojo
    .keyBy("country").window(
    SlidingEventTimeWindows.of(Time.seconds(10), Time.seconds(10)))
    .process(
    new FlinkEventTimeCountFunction()).name("count elements");



    The code seems all right without doubt,running without error as well.But ProcessWindowFunction never triggered.I tracked the Flink source code,find EventTimeTrigger never returns TriggerResult.FIRE,causing by TriggerContext.getCurrentWatermark returns Long.MIN_VALUE all the time.



    What's the proper way to process List in eventtime?Any suggestion will be appreciated.










    share|improve this question

























      0












      0








      0








      I have a continuing JSONArray data produced to Kafka topic,and I wanna process records with EventTime characteristic.In order to reach this goal,I have to assign watermark to each record which contained in the JSONArray.



      I didn't find a convenience way to achieve this goal.My solution is consuming data from DataStreamSource> ,then iterate List and collect Object to downstream with an anonymous ProcessFunction,finally assign watermark to the this downstream.



      The major code shows below:




      DataStreamSource<List<MockData>> listDataStreamSource = KafkaSource.genStream(env);
      SingleOutputStreamOperator<MockData> convertToPojo = listDataStreamSource
      .process(new ProcessFunction<List<MockData>, MockData>() {
      @Override
      public void processElement(List<MockData> value, Context ctx, Collector<MockData> out)
      throws Exception {
      value.forEach(mockData -> out.collect(mockData));
      }
      });
      convertToPojo.assignTimestampsAndWatermarks(
      new BoundedOutOfOrdernessTimestampExtractor<MockData>(Time.seconds(5)) {
      @Override
      public long extractTimestamp(MockData element) {
      return element.getTimestamp();
      }
      });
      SingleOutputStreamOperator<Tuple2<String, Long>> countStream = convertToPojo
      .keyBy("country").window(
      SlidingEventTimeWindows.of(Time.seconds(10), Time.seconds(10)))
      .process(
      new FlinkEventTimeCountFunction()).name("count elements");



      The code seems all right without doubt,running without error as well.But ProcessWindowFunction never triggered.I tracked the Flink source code,find EventTimeTrigger never returns TriggerResult.FIRE,causing by TriggerContext.getCurrentWatermark returns Long.MIN_VALUE all the time.



      What's the proper way to process List in eventtime?Any suggestion will be appreciated.










      share|improve this question














      I have a continuing JSONArray data produced to Kafka topic,and I wanna process records with EventTime characteristic.In order to reach this goal,I have to assign watermark to each record which contained in the JSONArray.



      I didn't find a convenience way to achieve this goal.My solution is consuming data from DataStreamSource> ,then iterate List and collect Object to downstream with an anonymous ProcessFunction,finally assign watermark to the this downstream.



      The major code shows below:




      DataStreamSource<List<MockData>> listDataStreamSource = KafkaSource.genStream(env);
      SingleOutputStreamOperator<MockData> convertToPojo = listDataStreamSource
      .process(new ProcessFunction<List<MockData>, MockData>() {
      @Override
      public void processElement(List<MockData> value, Context ctx, Collector<MockData> out)
      throws Exception {
      value.forEach(mockData -> out.collect(mockData));
      }
      });
      convertToPojo.assignTimestampsAndWatermarks(
      new BoundedOutOfOrdernessTimestampExtractor<MockData>(Time.seconds(5)) {
      @Override
      public long extractTimestamp(MockData element) {
      return element.getTimestamp();
      }
      });
      SingleOutputStreamOperator<Tuple2<String, Long>> countStream = convertToPojo
      .keyBy("country").window(
      SlidingEventTimeWindows.of(Time.seconds(10), Time.seconds(10)))
      .process(
      new FlinkEventTimeCountFunction()).name("count elements");



      The code seems all right without doubt,running without error as well.But ProcessWindowFunction never triggered.I tracked the Flink source code,find EventTimeTrigger never returns TriggerResult.FIRE,causing by TriggerContext.getCurrentWatermark returns Long.MIN_VALUE all the time.



      What's the proper way to process List in eventtime?Any suggestion will be appreciated.







      apache-flink flink-streaming






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      asked Nov 22 '18 at 6:32









      moyigukemoyiguke

      255




      255
























          1 Answer
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          0














          The problem is that you are applying the keyBy and window operations to the convertToPojo stream, rather than the stream with timestamps and watermarks (which you didn't assign to a variable).



          If you write the code more or less like this, it should work:



          listDataStreamSource = KafkaSource ...
          convertToPojo = listDataStreamSource.process ...
          pojoPlusWatermarks = convertToPojo.assignTimestampsAndWatermarks ...
          countStream = pojoPlusWatermarks.keyBy ...


          Calling assignTimestampsAndWatermarks on the convertToPojo stream does not modify that stream, but rather creates a new datastream object that includes timestamps and watermarks. You need to apply your windowing to that new datastream.






          share|improve this answer


























          • Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

            – moyiguke
            Nov 23 '18 at 9:51













          • I've expanded my answer to hopefully be more clear.

            – David Anderson
            Nov 23 '18 at 10:03











          • Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

            – moyiguke
            Nov 24 '18 at 14:24












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          1 Answer
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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          The problem is that you are applying the keyBy and window operations to the convertToPojo stream, rather than the stream with timestamps and watermarks (which you didn't assign to a variable).



          If you write the code more or less like this, it should work:



          listDataStreamSource = KafkaSource ...
          convertToPojo = listDataStreamSource.process ...
          pojoPlusWatermarks = convertToPojo.assignTimestampsAndWatermarks ...
          countStream = pojoPlusWatermarks.keyBy ...


          Calling assignTimestampsAndWatermarks on the convertToPojo stream does not modify that stream, but rather creates a new datastream object that includes timestamps and watermarks. You need to apply your windowing to that new datastream.






          share|improve this answer


























          • Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

            – moyiguke
            Nov 23 '18 at 9:51













          • I've expanded my answer to hopefully be more clear.

            – David Anderson
            Nov 23 '18 at 10:03











          • Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

            – moyiguke
            Nov 24 '18 at 14:24
















          0














          The problem is that you are applying the keyBy and window operations to the convertToPojo stream, rather than the stream with timestamps and watermarks (which you didn't assign to a variable).



          If you write the code more or less like this, it should work:



          listDataStreamSource = KafkaSource ...
          convertToPojo = listDataStreamSource.process ...
          pojoPlusWatermarks = convertToPojo.assignTimestampsAndWatermarks ...
          countStream = pojoPlusWatermarks.keyBy ...


          Calling assignTimestampsAndWatermarks on the convertToPojo stream does not modify that stream, but rather creates a new datastream object that includes timestamps and watermarks. You need to apply your windowing to that new datastream.






          share|improve this answer


























          • Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

            – moyiguke
            Nov 23 '18 at 9:51













          • I've expanded my answer to hopefully be more clear.

            – David Anderson
            Nov 23 '18 at 10:03











          • Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

            – moyiguke
            Nov 24 '18 at 14:24














          0












          0








          0







          The problem is that you are applying the keyBy and window operations to the convertToPojo stream, rather than the stream with timestamps and watermarks (which you didn't assign to a variable).



          If you write the code more or less like this, it should work:



          listDataStreamSource = KafkaSource ...
          convertToPojo = listDataStreamSource.process ...
          pojoPlusWatermarks = convertToPojo.assignTimestampsAndWatermarks ...
          countStream = pojoPlusWatermarks.keyBy ...


          Calling assignTimestampsAndWatermarks on the convertToPojo stream does not modify that stream, but rather creates a new datastream object that includes timestamps and watermarks. You need to apply your windowing to that new datastream.






          share|improve this answer















          The problem is that you are applying the keyBy and window operations to the convertToPojo stream, rather than the stream with timestamps and watermarks (which you didn't assign to a variable).



          If you write the code more or less like this, it should work:



          listDataStreamSource = KafkaSource ...
          convertToPojo = listDataStreamSource.process ...
          pojoPlusWatermarks = convertToPojo.assignTimestampsAndWatermarks ...
          countStream = pojoPlusWatermarks.keyBy ...


          Calling assignTimestampsAndWatermarks on the convertToPojo stream does not modify that stream, but rather creates a new datastream object that includes timestamps and watermarks. You need to apply your windowing to that new datastream.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 23 '18 at 10:03

























          answered Nov 22 '18 at 8:35









          David AndersonDavid Anderson

          6,77821424




          6,77821424













          • Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

            – moyiguke
            Nov 23 '18 at 9:51













          • I've expanded my answer to hopefully be more clear.

            – David Anderson
            Nov 23 '18 at 10:03











          • Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

            – moyiguke
            Nov 24 '18 at 14:24



















          • Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

            – moyiguke
            Nov 23 '18 at 9:51













          • I've expanded my answer to hopefully be more clear.

            – David Anderson
            Nov 23 '18 at 10:03











          • Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

            – moyiguke
            Nov 24 '18 at 14:24

















          Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

          – moyiguke
          Nov 23 '18 at 9:51







          Very glad to see you,and thanks for you prompt reply .I don't quite understand that,is it means user can not assign watermark to down stream other than source stream.As I find SourceFunction has collectWithTimestamp but none in Collector.

          – moyiguke
          Nov 23 '18 at 9:51















          I've expanded my answer to hopefully be more clear.

          – David Anderson
          Nov 23 '18 at 10:03





          I've expanded my answer to hopefully be more clear.

          – David Anderson
          Nov 23 '18 at 10:03













          Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

          – moyiguke
          Nov 24 '18 at 14:24





          Thank you so much !!! Your precise explanation enlightened me,following your guide and pseudocode,it works well now.

          – moyiguke
          Nov 24 '18 at 14:24




















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