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From: Jack Huang <jackhuang@mz.com>
Date: Tue, 16 Aug 2016 18:21:52 -0700
Message-ID: <CAK1f=arBus9U98E-J886SbvCfEdcLBxTXXkU_jUm=d_hMh7hQw@mail.gmail.com>
Subject: Cannot use WindowedStream.fold with EventTimeSessionWindows
To: user@flink.apache.org
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archived-at: Wed, 17 Aug 2016 01:22:38 -0000

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Hi all,

I want to window a series of events using SessionWindow and use fold
function to incrementally aggregate the result.

events
    .keyBy(_.id)
    .window(EventTimeSessionWindows.withGap(Time.minutes(1)))
    .fold(new Session)(eventFolder)

=E2=80=8B
However I get

java.lang.UnsupportedOperationException: Fold cannot be used with a
merging WindowAssigner.

=E2=80=8B

Does anyone have a workaround?


Thanks,
Jack

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<div dir=3D"ltr">Hi all,<div><br></div><div>I want to window a series of ev=
ents using SessionWindow and use fold function to incrementally aggregate t=
he result.</div><div class=3D"markdown-here-wrapper" style=3D""><pre style=
=3D"font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;fon=
t-size:1em;line-height:1.2em;margin:1.2em 0px"><code class=3D"hljs language=
-scala" style=3D"font-size:0.85em;font-family:Consolas,Inconsolata,Courier,=
monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1=
px solid rgb(234,234,234);border-radius:3px;display:inline;background-color=
:rgb(248,248,248);white-space:pre;overflow:auto;border-radius:3px;border:1p=
x solid rgb(204,204,204);padding:0.5em 0.7em;display:block!important;displa=
y:block;overflow-x:auto;padding:0.5em;color:rgb(51,51,51);background:rgb(24=
8,248,248)">events
    .keyBy(_.id)
    .window(<span class=3D"hljs-type" style=3D"color:rgb(68,85,136);font-we=
ight:bold">EventTimeSessionWindows</span>.withGap(<span class=3D"hljs-type"=
 style=3D"color:rgb(68,85,136);font-weight:bold">Time</span>.minutes(<span =
class=3D"hljs-number" style=3D"color:rgb(0,128,128)">1</span>)))
    .fold(<span class=3D"hljs-keyword" style=3D"color:rgb(51,51,51);font-we=
ight:bold">new</span> <span class=3D"hljs-type" style=3D"color:rgb(68,85,13=
6);font-weight:bold">Session</span>)(eventFolder)
</code></pre>
<div title=3D"MDH:PGRpdj5gYGBzY2FsYTwvZGl2PjxkaXY+PGRpdj5ldmVudHM8L2Rpdj48Z=
Gl2PjxzcGFuIGNsYXNz
PSIiIHN0eWxlPSJ3aGl0ZS1zcGFjZTogcHJlOyI+CTwvc3Bhbj4ua2V5QnkoXy5pZCk8L2Rpdj4=
8
ZGl2PjxzcGFuIGNsYXNzPSIiIHN0eWxlPSJ3aGl0ZS1zcGFjZTogcHJlOyI+CTwvc3Bhbj4ud2l=
u
ZG93KEV2ZW50VGltZVNlc3Npb25XaW5kb3dzLndpdGhHYXAoVGltZS5taW51dGVzKDEpKSk8L2R=
p
dj48ZGl2PjxzcGFuIGNsYXNzPSIiIHN0eWxlPSJ3aGl0ZS1zcGFjZTogcHJlOyI+CTwvc3Bhbj4=
u
Zm9sZChuZXcgU2Vzc2lvbikoZXZlbnRGb2xkZXIpPC9kaXY+PC9kaXY+PGRpdj5gYGA8L2Rpdj4=
=3D" style=3D"height:0;width:0;max-height:0;max-width:0;overflow:hidden;fon=
t-size:0em;padding:0;margin:0">=E2=80=8B</div></div><div></div><div>However=
 I get<br></div><div class=3D"markdown-here-wrapper" style=3D""><pre style=
=3D"font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;fon=
t-size:1em;line-height:1.2em;margin:1.2em 0px"><code style=3D"font-size:0.8=
5em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;pa=
dding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);bord=
er-radius:3px;display:inline;background-color:rgb(248,248,248);white-space:=
pre;overflow:auto;border-radius:3px;border:1px solid rgb(204,204,204);paddi=
ng:0.5em 0.7em;display:block!important">java.lang.UnsupportedOperationExcep=
tion: Fold cannot be used with a merging WindowAssigner.
</code></pre><div title=3D"MDH:PGRpdj5gYGA8L2Rpdj48ZGl2PmphdmEubGFuZy5VbnN1=
cHBvcnRlZE9wZXJhdGlvbkV4Y2VwdGlv
bjogRm9sZCBjYW5ub3QgYmUgdXNlZCB3aXRoIGEgbWVyZ2luZyBXaW5kb3dBc3NpZ25lci48YnI=
+
PC9kaXY+PGRpdj5gYGA8L2Rpdj48ZGl2PjwvZGl2Pg=3D=3D" style=3D"height:0;width:0=
;max-height:0;max-width:0;overflow:hidden;font-size:0em;padding:0;margin:0"=
>=E2=80=8B</div></div><div><br></div><div>Does anyone have a workaround?</d=
iv><div><br></div><div><br></div><div><br></div><div>Thanks,</div><div>Jack=
</div><div><br></div><div><br></div><div><br></div></div>

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