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From Maximilian Michels <...@apache.org>
Subject Re: Within interval for CEP - Wall Clock based or Event Timestamp based?
Date Fri, 12 Aug 2016 08:23:53 GMT
Hi Sameer,

That depends on the time characteristic you have chosen. If you have
set it to event time [1] then it will use event time, otherwise the
default is to use processing time.

When using event time, the element's timestamp is used to assign it to
the specified time windows in the patterns, regardless of the time it
actually arrives. The only exception being if the element arrives
after the Watermark, then only the single element will be processed
according to the patterns.

Cheers,
Max

[1] env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

On Thu, Aug 11, 2016 at 12:39 AM, Sameer W <sameer@axiomine.com> wrote:
> Hi,
>
> I am using EventTime but when the records get into the CEP PatternStream
> does the WITHIN interval refer to the wall clock time or the timestamps
> embedded in the event stream?
>
> If I provide WITHIN(Time.Seconds(5)) and in processing time I am getting
> events with timestamps in the range of 10 seconds (due to upstream emits),
> are all those events considered part of the pattern of their timestamps
> matter?
>
> Thanks,
> Sameer

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