操作依赖于什么规则来生成新的事件时间戳

ulydmbyx 于 2021-06-21 发布在 Flink

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我加入两个流创建一个新的流后操作。代码如下：

DataStream<NewTableA> join1 =
    oldTableADataStream
        .keyBy(t -> t.getFa3())
        .join(tableBDataStream)
        .where(new oldTableAKeySelector())
        .equalTo(new TableBKeySelector())
        .window(EventTimeSessionWindows.withGap(Time.milliseconds(WIN_GAP_TIME)))
        .allowedLateness(Time.milliseconds(allowedLateness))
        .apply(new oldTableAJoinTableBFunc());
        //.assignTimestampsAndWatermarks(new assignTSAndWMLastMax<>(maxOutOfOrderness));

   join1.process(
    new ProcessFunction<NewTableA, NewTableA>() {
      @Override
      public void processElement(NewTableA value, Context ctx, Collector<NewTableA> out)
          throws Exception {
        System.out.println(" NewTableA wmts:" + ctx.timerService().currentWatermark());
        System.out.println(" NewTableA ts:" + ctx.timestamp() + " " + value);
      }
    });

密码 oldTableAJoinTableBFunc 如下所示

public class oldTableAJoinTableBFunc implements JoinFunction<OldTableA, TableB, NewTableA> {

  @Override
  public NewTableA join(OldTableA oldTableA, TableB tableB) throws Exception {

    //System.out.println("join1 on");

    NewTableA newTableA = new NewTableA();

    newTableA.setPA1(oldTableA.getPa1());
    newTableA.setA2(oldTableA.getA2());
    newTableA.setFA3(oldTableA.getFa3());
    newTableA.setFA4(oldTableA.getFa4());
    newTableA.setB2(tableB.getB2());
    newTableA.setB3(tableB.getB3());
    // importance!!!
    newTableA.setTs(oldTableA.getTs());

    return newTableA;
  }
}

上面的例子， oldTableADataStream 加入 tableBDataStream 至 join1 事件时间流。
我发现了一个有趣的现象。中事件的时间戳 join1 是flink自动创建的。
当我创建的测试数据 oldTableADataStream 以及 tableBDataStream ，我故意设置了所有1000000010和100000044。但是在join和apply函数之后，新流中的事件时间戳 join1 由flink更改，打印如下：

NewTableA wmts:**1000000042**
 NewTableA ts:**1000000143**NewTableA{PA1=10, A2='a20', FA3=21, B2='b21', B3='b31', FA4=39, C2='null', FC3=null, D2='null', D3='null', ts=**1000000011**}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA ts:**1000000143**NewTableA{PA1=1, A2='a20', FA3=20, B2='b20', B3='b30', FA4=30, C2='null', FC3=null, D2='null', D3='null', ts=**1000000010**}
 NewTableA wmts:1000000042
 NewTableA ts:1000000143 NewTableA{PA1=11, A2='a20', FA3=21, B2='b21', B3='b31', FA4=40, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA ts:1000000135 NewTableA{PA1=21, A2='a20', FA3=22, B2='b22', B3='b32', FA4=30, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA ts:1000000138 NewTableA{PA1=38, A2='a20', FA3=23, B2='b23', B3='b33', FA4=34, C2='null', FC3=null, D2='null', D3='null', ts=1000000015}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA ts:1000000138 NewTableA{PA1=57, A2='a20', FA3=24, B2='b24', B3='b34', FA4=36, C2='null', FC3=null, D2='null', D3='null', ts=1000000018}
 NewTableA ts:1000000143 NewTableA{PA1=2, A2='a20', FA3=20, B2='b20', B3='b30', FA4=31, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA wmts:1000000042
 NewTableA ts:1000000143 NewTableA{PA1=12, A2='a20', FA3=21, B2='b21', B3='b31', FA4=41, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA ts:1000000135 NewTableA{PA1=22, A2='a20', FA3=22, B2='b22', B3='b32', FA4=31, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA wmts:1000000042
 NewTableA ts:1000000138 NewTableA{PA1=58, A2='a20', FA3=24, B2='b24', B3='b34', FA4=36, C2='null', FC3=null, D2='null', D3='null', ts=1000000018}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA ts:1000000143 NewTableA{PA1=13, A2='a20', FA3=21, B2='b21', B3='b31', FA4=42, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA ts:1000000138 NewTableA{PA1=39, A2='a20', FA3=23, B2='b23', B3='b33', FA4=34, C2='null', FC3=null, D2='null', D3='null', ts=1000000015}
 NewTableA wmts:1000000042
 NewTableA ts:1000000138 NewTableA{PA1=59, A2='a20', FA3=24, B2='b24', B3='b34', FA4=36, C2='null', FC3=null, D2='null', D3='null', ts=1000000018}
 NewTableA ts:1000000135 NewTableA{PA1=23, A2='a20', FA3=22, B2='b22', B3='b32', FA4=32, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA ts:1000000143 NewTableA{PA1=3, A2='a20', FA3=20, B2='b20', B3='b30', FA4=32, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 NewTableA ts:1000000143 NewTableA{PA1=14, A2='a20', FA3=21, B2='b21', B3='b31', FA4=43, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA ts:1000000138 NewTableA{PA1=40, A2='a20', FA3=23, B2='b23', B3='b33', FA4=34, C2='null', FC3=null, D2='null', D3='null', ts=1000000016}
 NewTableA ts:1000000135 NewTableA{PA1=24, A2='a20', FA3=22, B2='b22', B3='b32', FA4=33, C2='null', FC3=null, D2='null', D3='null', ts=1000000011}
 NewTableA wmts:1000000042
 NewTableA wmts:1000000042
 ......

似乎没有规则创建新事件的时间戳，如何计算1000000143、1000000138和1000000135等等？似乎与水印无关，因为时间戳水印是100000042，它同时与事件的时间戳不同。
操作依赖什么规则来生成新的事件时间戳，我还没有找到官方的指令，谁能给它们一个链接？

apache-flink

来源：https://stackoverflow.com/questions/63245270/what-rules-the-operation-relies-on-to-generate-the-new-timestamp-of-events