Question

我正在使用基于Flink事件时间的窗口。但是当我发送kafka消息程序时不会执行窗口操作。我做了所有文档所说的事情，但是无法解决问题，需要任何帮助，在此先感谢

    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment environment = StreamExecutionEnvironment.getExecutionEnvironment();
        environment.getConfig();
        environment.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
        environment.setParallelism(1);
        Properties props = new Properties();
        props.setProperty("bootstrap.servers", "localhost:9092");
        props.setProperty("group.id","event-group");

        FlinkKafkaConsumer<EventSalesQuantity> consumer = new FlinkKafkaConsumer<EventSalesQuantity>("EventTopic",new EventSerializationSchema(),props);
        DataStream<EventSalesQuantity> eventDataStream = environment.addSource(consumer);

        KeyedStream<EventSalesQuantity, String> keyedEventStream = eventDataStream.assignTimestampsAndWatermarks( new AssignerWithPeriodicWatermarksImpl()).
           keyBy(new KeySelector<EventSalesQuantity, String>() {
               @Override
               public String getKey(EventSalesQuantity eventSalesQuantity) throws Exception {
                   return  eventSalesQuantity.getDealer();
               }
           });

        DataStream<Tuple2<EventSalesQuantity,Integer>> eventSinkStream = keyedEventStream.timeWindow(Time.seconds(5)).aggregate(new AggregateImpl());
        eventSinkStream.addSink(new FlinkKafkaProducer<Tuple2<EventSalesQuantity, Integer>>("localhost:9092","SinkEventTopic",new EventSinkSerializationSchema()));
        eventSinkStream.print();
        environment.execute();
    }
}




public class AssignerWithPeriodicWatermarksImpl implements AssignerWithPeriodicWatermarks<EventSalesQuantity> {
    private final long maxOutOfOrderness = 3500; 
    private long currentMaxTimestamp;

    @Override
    public long extractTimestamp(EventSalesQuantity element, long previousElementTimestamp) {
        long timestamp = DateUtils.getDateFromString(element.getTransactionDate()).getTime();
        currentMaxTimestamp = Math.max(timestamp, currentMaxTimestamp);
        return timestamp;
    }

    @Override
    public Watermark getCurrentWatermark() {
        // return the watermark as current highest timestamp minus the out-of-orderness bound
        return new Watermark(currentMaxTimestamp - maxOutOfOrderness);
    }

“ 2019-06-21T09：43：01” “ 2019-06-21T09：43：03”

我用这些时间戳发送2条消息，但没有输出。

Answer 1

您的事件时间窗口长5秒。包含这些事件的窗口只有在看到时间戳至少为2019-06-21T09：43：05的水印时才会被触发。
在将maxOutOfOrderness设置为3500毫秒的情况下，您的水印生成器将不会生成足以触发窗口的水印，直到它看到时间戳至少为2019-06-21T09：43：08.500的事件为止。

基于事件时间的窗口不会触发

1 个答案: