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From Yassin Marzouki <yassmar...@gmail.com>
Subject Re: If I chain two windows, what event-time would the second window have?
Date Wed, 27 Jul 2016 12:04:24 GMT
Hi Kostas,

Thank you very much for the explanation.

Best,
Yassine

On Wed, Jul 27, 2016 at 1:09 PM, Kostas Kloudas <k.kloudas@data-artisans.com
> wrote:

> Hi Yassine,
>
> When the WindowFunction is applied to the content of a window, the
> timestamp of the resulting record
> is the window.maxTimestamp, which is the endOfWindow-1.
>
> You can imaging if you have a Tumbling window from 0 to 2000, the result
> will have a timestamp of 1999.
> Window boundaries are closed in the start and open at the end timestamp,
> or [start, end).
>
> If you want to play around, I would suggest checking out the tests in the
> WindowOperatorTest class.
>
> There you can do experiments and figure out how Flinkā€™s windowOperator
> works internally and what is the
> interplay between windowAssingers, triggers, and the windowOperator.
>
> Hope this helps,
> Kostas
>
> On Jul 27, 2016, at 8:41 AM, Yassin Marzouki <yassmarzou@gmail.com> wrote:
>
> Hi all,
>
> Say I assign timestamps to a stream and then apply a transformation like
> this:
>
>
> stream.keyBy(0).timeWindow(Time.hours(5)).reduce(count).timeWindowAll(Time.days(1)).apply(transformation)
>
> Now, when the first window is applied, events are aggregated based on
> their timestamps, but I don't understand what timestamp will be assigned to
> the aggregated result of the reduce operation for the second window to
> process it. Could you please explain it? Thank you.
>
> Best,
> Yassine
>
>
>

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