Sure thanks a lot! Bowen and Fabian. I will create the JIRA and also submit a PR with a better comment.
-------------------------------------------------- Dhruv Kumar PhD Candidate Department of Computer Science and Engineering University of Minnesota www.dhruvkumar.me > On May 28, 2018, at 03:50, Fabian Hueske <fhue...@gmail.com> wrote: > > I agree, this should be fixed. > > Thanks for noticing, Dhruv. > Would you mind creating a JIRA for this? > > Thank you, > Fabian > > 2018-05-28 8:39 GMT+02:00 Bowen Li <bowenl...@gmail.com > <mailto:bowenl...@gmail.com>>: > Hi Dhruv, > > I can see it's confusing, and it does seem the comment should be improved. > You can find concrete explanation of tumbling window and relative arguments > at > https://ci.apache.org/projects/flink/flink-docs-master/dev/stream/operators/windows.html#tumbling-windows > > <https://ci.apache.org/projects/flink/flink-docs-master/dev/stream/operators/windows.html#tumbling-windows> > > Feel free to open a PR with better comment. > > Thanks, > Bowen > > > > On Sun, May 27, 2018 at 12:43 PM, Dhruv Kumar <gargdhru...@gmail.com > <mailto:gargdhru...@gmail.com>> wrote: > Hi > > I was looking at TumblingProcessingTimeWindows.java > <https://github.com/apache/flink/blob/master/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/assigners/TumblingProcessingTimeWindows.java> > and was a bit confused with the documentation at the start of this class. It > says the following: > > /** > * A {@link WindowAssigner} that windows elements into windows based on the > current > * system time of the machine the operation is running on. Windows cannot > overlap. > * > * <p>For example, in order to window into windows of 1 minute, every 10 > seconds: > * <pre> {@code > * DataStream<Tuple2<String, Integer>> in = ...; > * KeyedStream<String, Tuple2<String, Integer>> keyed = in.keyBy(...); > * WindowedStream<Tuple2<String, Integer>, String, TimeWindows> windowed = > * keyed.window(TumblingProcessingTimeWindows.of(Time.of(1, MINUTES), > Time.of(10, SECONDS)); > * } </pre> > */ > > > It says one can have tumbling windows of 1 minute, every 10 seconds. Doesn’t > this become a sliding window then? The SlidingProcessTimeWindows.java > <https://github.com/apache/flink/blob/master/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/assigners/SlidingProcessingTimeWindows.java> > has the exact same documentation with just one tiny change (“Windows can > possibly overlap”). It seems to me that in the above documentation, the > second Time argument of 10 seconds is for providing the window offset (as > confirmed here > <https://github.com/apache/flink/blob/master/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/assigners/TumblingProcessingTimeWindows.java#L92>) > and not for starting the tumbling window every 10 seconds. > > Thanks > > > -------------------------------------------------- > Dhruv Kumar > PhD Candidate > Department of Computer Science and Engineering > University of Minnesota > www.dhruvkumar.me <http://www.dhruvkumar.me/> > >
