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From: Sameer W <sameer@axiomine.com>
Date: Tue, 26 Jul 2016 21:21:25 -0400
Message-ID: <CANvT7L0YW8xiVLrPo0NvvmJOfUsNSVhpDVE6PUgp2mdLq1SVng@mail.gmail.com>
Subject: CEP and Within Clause
To: user@flink.apache.org
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archived-at: Wed, 27 Jul 2016 01:21:31 -0000

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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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<div dir=3D"ltr">Hi,<div><br></div><div>It looks like the WithIn clause of =
CEP uses Tumbling Windows. I could get it to use Sliding windows by using a=
n upstream pipeline which uses Sliding Windows and produces repeating eleme=
nts (in each sliding window) and applying a Watermark assigner on the resul=
ting stream with elements duplicated. I wanted to use the &quot;followedBy&=
quot; pattern where there is a strong need for sliding windows.</div><div><=
br></div><div>Is there a plan to add sliding windows to the within clause a=
t some point?=C2=A0</div><div><br></div><div>The=C2=A0<span style=3D"color:=
inherit;font-family:Menlo,Monaco,Consolas,&quot;Courier New&quot;,monospace=
;font-size:inherit;white-space:pre-wrap;line-height:1.42857;background-colo=
r:transparent">PatternStream </span>class&#39;s &quot;select&quot; and &quo=
t;flatSelect&quot; have overloaded versions which take PatternTimeOut varia=
ble. Is there a way to insert some of those elements back to the front of t=
he stream. Say I am trying to find a pattern where two temperature readings=
 &gt;150 within 6 second window should raise an alert. If only one was foun=
d, 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 occ=
urring in the next 6 seconds. If I can do that, I don&#39;t need sliding wi=
ndows. Else I cannot avoid using them for such scenarios.</div><div><br></d=
iv><div>Thanks,</div><div>Sameer</div></div>

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