Hi Soheil,
> wait 8 milliseconds (according to my code) to see if any other data with
the same key received or not and after 8 millisecond it will be triggered.
Yes, but the time is event time, so if there is no data from source the
time won't be advanced.
There are some reasons why the event time has not been advanced:
1. There are no data from the source
2. One of the source parallelisms doesn't have data
3. The time field, i.e, Long in Tuple3, should be millisecond instead of
second.
4. Data should cover a longer time spam than the window size to advance the
event time.
Best, Hequn
On Wed, Jul 18, 2018 at 3:53 PM, Soheil Pourbafrani <soheil.i...@gmail.com>
wrote:
> Hi,
>
> In a datastream processing problem, the source generated data every 8
> millisecond and timestamp is a field of the data. In default Flink time
> behavior data enter the time window but when I set Flink time to EventTime
> it will output nothing! Here is the code:
>
> env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
>
> SingleOutputStreamOperator<Tuple3<String,Long, JSONObject>> res =
> aggregatedTuple
> .assignTimestampsAndWatermarks(new
> BoundedOutOfOrdernessTimestampExtractor<Tuple3<String, Long,
> JSONObject>>(Time.milliseconds(8)) {
>
> @Override
> public long extractTimestamp(Tuple3<String, Long, JSONObject>
> element) {
> return element.f1 ;
> }
> }).keyBy(1).timeWindow(Time.milliseconds(8))
> .allowedLateness(Time.milliseconds(3))
> .sideOutputLateData(lateOutputTag)
> .reduce(processing...);
> DataStream<Tuple3<String, Long, JSONObject>> lateData =
> res.getSideOutput(lateOutputTag);
> res.print();
>
> What is the problem with my code?
> According to the Flink documents, my understanding about EventTime is that
> for example in case of time window when a new data received it start a new
> (logical window) based on new data event timestamp and wait 8 milliseconds
> (according to my code) to see if any other data with the same key received
> or not and after 8 millisecond (from timestamp of the first element of the
> window) it will be triggered. Since data source generated data in a
> constant periodic interval, I set a watermarck of 8, too. Is my
> understanding about Flink window in EventTime correct?
>
