Strange behaviour of windows

Posted by Dawid Wysakowicz on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Strange-behaviour-of-windows-tp3949.html

Hi,

I have recently experimented a bit with windowing and event-time mechanism in flink and either I do not understand how should it work or there is some kind of a bug.

I have prepared two Source Functions. One that emits watermark itself and one that does not, but I have prepared a TimestampExtractor that should produce same results that the previous Source Function, at least from my point of view.

Afterwards I've prepared a simple summing over an EventTimeTriggered Sliding Window.

What I expected is a sum of 3*(t_sum) property of Event regardless of the sleep time in Source Function. That is how the EventTimeSourceFunction works, but for the SourceFunction it depends on the sleep and does not equals 3*(t_sum).

I have done some debugging and for the SourceFunction the output of ExtractTimestampsOperator does not chain to the aggregator operator(the property output.allOutputs is empty).

Do I understand the mechanism correctly and should my code work as I described? If not could you please explain a little bit? The code I've attached to this email.

I would be grateful.

Regards

Dawid Wysakowicz