Watermark won't advance in ProcessFunction

Posted by 杨力 on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Watermark-won-t-advance-in-ProcessFunction-tp30709.html

I'm going to sort elements in a PriorityQueue and set up timers at (currentWatermark + 1), following the instructions in https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/operators/process_function.html#timer-coalescing.

However, it seems that context.timerService().currentWatermark() always returns Long.MinValue and my onTimer will never be called. Here's minimal program to reproduce the problem. Am I missing something?

```

val sEnv = StreamExecutionEnvironment.getExecutionEnvironment

sEnv.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)

sEnv.setParallelism(argOps.parallelism())

sEnv.fromCollection(Seq[Long](1, 2, 3)).assignAscendingTimestamps(identity[Long])

    .process(new ProcessFunction[Long, Long] {

      override def processElement(i: Long, context: ProcessFunction[Long, Long]#Context, collector: Collector[Long]): Unit = {

        collector.collect(context.timerService().currentWatermark())

      }

    }).print()

sEnv.execute()

```

```

-9223372036854775808

-9223372036854775808

-9223372036854775808

```