https://ci.apache.org/projects/flink/flink-docs-release-1.10/zh/dev/event_timestamps_watermarks.html
```Both timestamps and watermarks are specified as milliseconds since the Java epoch of 1970-01-01T00:00:00Z.``` 看一下这个， 从0 timestamp开始切分 在 2020/4/4 下午6:20，“Benchao Li”<[email protected]> 写入: 你的watermark不是56000，而是1000000056000吧。所以应该是[1000000053000, 1000000056000)是一个窗口吧。 忝忝向仧 <[email protected]> 于2020年4月4日周六 下午6:16写道： > 下发新的? > > > 4是一个kafka的source，3是另外一个kafka的source. > 如果按照3秒的一个窗口 > watermark触发窗口的条件是watermark_time>=window_endtime > > > 也就是说[55000,57000)应该是一个窗口的. > > > 我是这么理解的，但是结果56000后就输出了 > > > > currentTimeStamp: 1000000055000,Key:1,EventTime:1000000055000,前一条数据的水位线:0 > 4> (1,tom1,1000000055000) > > currentTimeStamp: 1000000056000,Key:1,EventTime:1000000056000,前一条数据的水位线:1000000055000 > 4> (1,tom2,1000000056000) > > currentTimeStamp: 1000000055000,Key:1,EventTime:1000000055000,前一条数据的水位线:0 > 3> (1,jerry1,1000000055000) > > currentTimeStamp: 1000000056000,Key:1,EventTime:1000000056000,前一条数据的水位线:1000000055000 > 3> (1,jerry2,1000000056000) > 2> tom1=jerry1 > > > > > > > > ------------------ 原始邮件 ------------------ > 发件人: "lee.roval"<[email protected]>; > 发送时间: 2020年4月4日(星期六) 晚上6:10 > 收件人: "[email protected]"<[email protected]>; > > 主题: Re: Flink双流Join问题 > > > > 56000后不是下发新的watermark了嘛 > > 在 2020/4/4 下午5:57，“忝忝向仧”<[email protected]> 写入: > > 各位好:&nbsp; &nbsp; &nbsp; &nbsp; > Flink双流Join遇到一个问题，能否解释下，谢谢. > &nbsp; &nbsp; &nbsp; &nbsp; > ds1和ds2分别读取kafka两个流数据，使用event time和watermark特性，3s的一个翻滚窗口，定义如下: > &nbsp; &nbsp; &nbsp; &nbsp; > 最后，join输出的时候，为什么触发窗口的数据第二条就触发了? > &nbsp; &nbsp; &nbsp; &nbsp; > 按照水印的触发条件应该是watermark_time&gt;=window_endtime.那么，这里应该是1000000057000这条数据来了后才会触发，但是结果却是56000就触发了.为什么? > > > > 定义的代码如下: > DataStream<String&gt; stream1 = env > > .addSource(new FlinkKafkaConsumer09<String&gt;("stream1", new > SimpleStringSchema(), properties).setStartFromLatest()) > > .assignTimestampsAndWatermarks( > > new AssignerWithPeriodicWatermarks<String&gt;() { > > long currentTimeStamp = 0L; > > long maxDelayAllowed = 0L; > > long currentWaterMark; > > @Nullable > > @Override > > public Watermark getCurrentWatermark() { > > currentWaterMark = currentTimeStamp-maxDelayAllowed; > > return new Watermark(currentWaterMark); > > } > > @Override > > public long extractTimestamp(String s, long l) { > > String[] arr= s.split(" "); > > long timeStamp = Long.parseLong(arr[2]); > > currentTimeStamp = Math.max(timeStamp, currentTimeStamp); > > System.out.println("currentTimeStamp: " + currentTimeStamp +",Key:" + > arr[0] + ",EventTime:" + timeStamp + ",前一条数据的水位线:" + currentWaterMark); > > return timeStamp; > > } > > } > ); > > DataStream<Tuple3<String,String,String&gt;&gt; > ds1 = stream1.map(new MapFunction<String, > Tuple3<String,String,String&gt;&gt;() { > @Override > public Tuple3<String, > String,String&gt; map(String s1) throws Exception { > > String[] arr = s1.split(" "); > return > Tuple3.of(arr[0],arr[1],arr[2]); > } > }); > > ds1.print(); > DataStream<String&gt; stream2 = env > > .addSource(new FlinkKafkaConsumer09<String&gt;("stream2", new > SimpleStringSchema(), properties).setStartFromLatest()) > > .assignTimestampsAndWatermarks( > > new AssignerWithPeriodicWatermarks<String&gt;() { > > long currentTimeStamp = 0L; > > long maxDelayAllowed = 0L; > > long currentWaterMark; > > @Nullable > > @Override > > public Watermark getCurrentWatermark() { > > currentWaterMark = currentTimeStamp-maxDelayAllowed; > > return new Watermark(currentWaterMark); > > } > > @Override > > public long extractTimestamp(String s, long l) { > > String[] arr= s.split(" "); > > long timeStamp = Long.parseLong(arr[2]); > > currentTimeStamp = Math.max(timeStamp, currentTimeStamp); > > System.out.println("currentTimeStamp: " + currentTimeStamp +",Key:" + > arr[0] + ",EventTime:" + timeStamp + ",前一条数据的水位线:" + currentWaterMark); > > return timeStamp; > > } > > } > ); > > DataStream<Tuple3<String,String,String&gt;&gt; > ds2 =stream2.map(new MapFunction<String, > Tuple3<String,String,String&gt;&gt;() { > @Override > public > Tuple3<String,String,String&gt; map(String s2) throws Exception { > String > [] arr = s2.split(" "); > return > Tuple3.of(arr[0],arr[1],arr[2]); > } > }); > ds2.print(); > ds1.join(ds2).where(new KeySelector<Tuple3<String, > String,String&gt;,String&gt;() { > @Override > public String > getKey(Tuple3<String, String,String&gt; value) throws Exception { > return > value.f0; > } > }).equalTo(new KeySelector<Tuple3<String, String > ,String&gt;, String&gt;() { > @Override > public String > getKey(Tuple3<String, String,String&gt; value) throws Exception { > return > value.f0; > } > }) > .window(TumblingEventTimeWindows.of(Time.seconds(3))) > .apply(new JoinFunction<Tuple3<String, > String,String&gt;, Tuple3<String, String,String&gt;, > String&gt;() { > @Override > public String > join(Tuple3<String, String,String&gt; value1, Tuple3<String, > String,String&gt; value2) throws Exception { > return > value1.f1 + "=" + value2.f1; > } > }).print(); > 结果如下: > currentTimeStamp: > 1000000055000,Key:1,EventTime:1000000055000,前一条数据的水位线:0 > 4&gt; (1,tom1,1000000055000) > currentTimeStamp: > 1000000056000,Key:1,EventTime:1000000056000,前一条数据的水位线:1000000055000 > 4&gt; (1,tom2,1000000056000) > currentTimeStamp: > 1000000055000,Key:1,EventTime:1000000055000,前一条数据的水位线:0 > 3&gt; (1,jerry1,1000000055000) > currentTimeStamp: > 1000000056000,Key:1,EventTime:1000000056000,前一条数据的水位线:1000000055000 > 3&gt; (1,jerry2,1000000056000) > 2&gt; tom1=jerry1 -- Benchao Li School of Electronics Engineering and Computer Science, Peking University Tel:+86-15650713730 Email: [email protected]; [email protected]
