I have a requirement where I want to do aggregation on one data stream every 5 minutes, a different data stream every 1 minute. I wrote a example code to test this out but the behavior is different from what I expected , I expected the window2 to be called 5 times, and window 1 to called once , but in a 5 minute interval the window 1 is called once and window2 is called only once, have I understood the windowed function incorrectly, does the input play a role in no of times a window apply is called. I use the nc command to write to the socket port 9999 and 9998.
import org.apache.flink.streaming.api.TimeCharacteristic import org.apache.flink.streaming.api.scala._ import org.apache.flink.streaming.api.scala.function.AllWindowFunction import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows import org.apache.flink.streaming.api.windowing.time.Time import org.apache.flink.streaming.api.windowing.windows.{GlobalWindow, TimeWindow} import org.apache.flink.util.Collector import org.apache.flink.streaming.api.windowing.windows.Window object WindowWordCount { def main(args: Array[String]) { val env = StreamExecutionEnvironment.getExecutionEnvironment env.setStreamTimeCharacteristic(TimeCharacteristic.IngestionTime) val text = env.socketTextStream("localhost", 9999) val text1 = env.socketTextStream("localhost", 9998) val stream:DataStream[String] = text.flatMap { _.toLowerCase.split("\\W+") filter { _.nonEmpty } } val count = stream.windowAll(TumblingEventTimeWindows.of(Time.minutes(5))).apply { new MyAllWindowFunction } count.print val counts1 = text1.flatMap { _.toLowerCase.split("\\W+") filter { _.nonEmpty } } .windowAll(TumblingEventTimeWindows.of(Time.minutes(1))).apply { new MyAllWindowFunction2 } counts1.print env.execute("Window Stream WordCount") } class MyAllWindowFunction extends AllWindowFunction[String,String,TimeWindow] { def apply(window : TimeWindow, input : scala.Iterable[String], out : org.apache.flink.util.Collector[String]): Unit = { System.out.println("timed window1 is called") } } class MyAllWindowFunction2 extends AllWindowFunction[String,String,TimeWindow] { def apply(window : TimeWindow, input : scala.Iterable[String], out : org.apache.flink.util.Collector[String]): Unit = { System.out.println("timed window2 is called") } } } The output was: timed window2 is called timed window1 is called