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From Sameer W <sam...@axiomine.com>
Subject CEP and Within Clause
Date Wed, 27 Jul 2016 01:21:25 GMT

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.


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