Hi,
I created a visualization to help explain the situation:
http://s21.postimg.org/dofhcw52f/window_example.png
The SlidingProcessingTimeWindows assigner assigns elements to windows based on
the current processing time. The CountTrigger only fires if a window contains 5
elements (or more). In your test the windows for a, c and e fell into case b
because you probably entered the letters very fast. For elements b and d we
have case a The elements were far enough apart or you happened to enter them
right on a window boundary such that only one window contains all of them. The
other windows don’t contain enough elements to reach 5. In my drawing window 1
contains 5 elements while window 2 only contains 3 of those elements.
I hope this helps.
Cheers,
Aljoscha
> On 12 Mar 2016, at 19:19, Vishnu Viswanath <vishnu.viswanat...@gmail.com>
> wrote:
>
> Hi All,
>
>
> I have the below code
>
>
> val sev = StreamExecutionEnvironment.getExecutionEnvironment
> val socTextStream = sev.socketTextStream("localhost",4444)
>
> val counts = socTextStream.flatMap{_.split("\\s")}
> .map { (_, 1) }
> .keyBy(0)
> .window(SlidingProcessingTimeWindows.of(Time.seconds(20),Time.seconds(10)))
> .trigger(CountTrigger.of(5))
> .sum(1)
>
> counts.print()
> sev.execute()
>
> I am sending messages to the port 4444 using nc -lk 4444
> This is my sample input
>
> a
> a
> a
> a
> a
> b
> b
> b
> b
> b
> c
> c
> c
> c
> c
> d
> d
> d
> d
> d
> e
> e
> e
> e
> e
>
> I am sending 5 of each letter since I have a Count Trigger of 5. I was
> expecting that for each 5 character, the code will print 5, i.e., (a,5) (b,5)
> etc. But the output I am getting is little confusing.
> Output:
>
> 1> (a,5)
> 1> (a,5)
> 1> (b,5)
> 2> (c,5)
> 2> (c,5)
> 1> (d,5)
> 1> (e,5)
> 1> (e,5)
>
> As you can see, for some character the count is printed twice(a,c,e) and for
> some characters it is printed only once (b,d). I am not able to figure out
> what is going on. I think it may have something to do with the
> SlidingProcessingTimeWindow but I am not sure.
> Can someone explain me what is going on?
>
>
> Thanks and Regards,
> Vishnu Viswanath
> www.vishnuviswanath.com
>
