Thanks Till,

In that case if I have a pattern -
First = T > 30
Followed By = T > 50
Within 10 minutes

If I get the following sequence of events within 10 minutes
T=31, T=51, T=31, T=51

I assume the alert will fire twice now.

But what happens if the last T=51 arrives in the 11th minute. If the
partially matched pattern is discarded after 10 minutes how will the system
detect T=51. Or do you mean that that timer (for the within clause) is
reset each time the patter T>30 matches. In that case it would fire!

Thanks,
Sameer

On Tue, Aug 2, 2016 at 10:02 AM, Till Rohrmann <trohrm...@apache.org> wrote:

> Hi Sameer,
>
> the within clause of CEP uses neither tumbling nor sliding windows. It is
> more like a session window which is started whenever an element which
> matches the starting condition arrives. As long as new events which fulfill
> the pattern definition arrive within the length of the window, they will be
> added. If the pattern should not be completed within the specified time
> interval, the partially matched pattern will be discarded. If you've
> specified a timeout handler, then the timeout handler is called with the
> partial pattern.
>
> At the moment, there is no way to re-insert elements in the upstream.
> Actually there is also no need for it because the CEP operator will detect
> the alert patterns if there are two temperature readings > 150 within 6
> seconds.
>
> Cheers,
> Till
>
>
>
> On Tue, Aug 2, 2016 at 5:12 AM, Aljoscha Krettek <aljos...@apache.org>
> wrote:
>
>> +Till, looping him in directly, he probably missed this because he was
>> away for a while.
>>
>>
>>
>> On Tue, 26 Jul 2016 at 18:21 Sameer W <sam...@axiomine.com> wrote:
>>
>>> Hi,
>>>
>>> It looks like the WithIn clause of CEP uses Tumbling Windows. I could
>>> get it to use Sliding windows by using an upstream pipeline which uses
>>> Sliding Windows and produces repeating elements (in each sliding window)
>>> and applying a Watermark assigner on the resulting stream with elements
>>> duplicated. I wanted to use the "followedBy" pattern where there is a
>>> strong need for sliding windows.
>>>
>>> Is there a plan to add sliding windows to the within clause at some
>>> point?
>>>
>>> The PatternStream class's "select" and "flatSelect" have overloaded
>>> versions which take PatternTimeOut variable. Is there a way to insert some
>>> of those elements back to the front of the stream. Say I am trying to find
>>> a pattern where two temperature readings >150 within 6 second window should
>>> raise an alert. If only one was found, can I insert that one back in the
>>> front of the stream on that task node (for that window pane) so that I can
>>> find a pattern match in the events occurring in the next 6 seconds. If I
>>> can do that, I don't need sliding windows. Else I cannot avoid using them
>>> for such scenarios.
>>>
>>> Thanks,
>>> Sameer
>>>
>>
>

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