Hi, an important concept of the Flink API is that transformations do not modify the original stream (or dataset) but return a new stream with the modifications in place. In your example the result of the extractTimestamps() call should be used for further processing. I attached your source code with the required modifications.
Other than that, I think you understood the watermarks quite well. :D Let us know if you need more information. Cheers, Aljoscha
FlinkWindows.scala
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> On 07 Dec 2015, at 20:34, Dawid Wysakowicz <wysakowicz.da...@gmail.com> wrote: > > Forgot to mention. I've checked it both on 0.10 and current master. > > 2015-12-07 20:32 GMT+01:00 Dawid Wysakowicz <wysakowicz.da...@gmail.com>: > 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 > > >
