Hi, a Trigger is an *additional* condition for intermediate (early) evaluation of the window. Thus, it is not "or-ed" to the basic window definition.
If you want to have an or-ed window condition, you can customize it by
specifying your own window definition.
> dataStream.window(new MyOwnWindow() extends WindowAssigner { /* put your code
> here */ );
-Matthias
On 11/26/2015 11:40 PM, Anwar Rizal wrote:
> Hi all,
>
> From the documentation:
> "The |Trigger| specifies when the function that comes after the window
> clause (e.g., |sum|, |count|) is evaluated (“fires”) for each window."
>
> So, basically, if I specify:
>
> |keyedStream
> .window(TumblingTimeWindows.of(Time.of(5, TimeUnit.SECONDS))
> .trigger(CountTrigger.of(100))|
>
> |
> |
>
> |The execution of the window function is triggered when the count reaches 100
> in the time window of 5 seconds. If you have a system that never reaches 100
> in 5 seconds, basically you will never have the window fired.|
>
> |
> |
>
> |My question is, what would be the best option to have behavior as follow:|
>
> |The execution of the window function is triggered when 5 seconds is reached
> or 100 events are received before 5 seconds.|
>
>
> I think of implementing my own trigger that looks like CountTrigger, but that
> will fire also when the end of time window is reached (at the moment, it just
> returns Continue, instead of Fired). But maybe there's a better way ?
>
> Is there a reason why CountTrigger is implemented as it is implemented today,
> and not as I described above (5 seconds or 100 events reached, whichever
> comes first).
>
>
> Thanks,
>
> Anwar.
>
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