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From Kien Truong <duckientru...@gmail.com>
Subject Re: How can i merge more than one flink stream
Date Thu, 20 Jul 2017 05:39:00 GMT

To expand on Fabian's answer, there's a few API for join. 

* connect - you have to provide a CoprocessFunction. 

* window join/cogroup - you provideĀ  key selector functions, a time window and a join/cogroup

With the first method, you have to write more code, in exchange for much more flexible join


On Jul 20, 2017, 01:55, at 01:55, Fabian Hueske <fhueske@gmail.com> wrote:
>there are basically two operations to merge streams.
>1. Union simply merges the input streams such that the resulting stream
>the records of all input streams. Union is a built-in operator in the
>DataStream API. For that all streams must have the same data type.
>2. Join connects records of streams according to a join condition. When
>joining streams, this condition is often based on some time bounds.
>usually needs to be manually implemented using a stateful
>Once the streams are unioned or joined, you can apply a time-window on
>result stream.
>Best, Fabian
>2017-07-19 9:05 GMT+02:00 Jone Zhang <joyoungzhang@gmail.com>:
>> I have three data streams
>> 1. app exposed and click
>> 2. app download
>> 3. app install
>> How can i merge the streams to create a unified stream,then compute
>it on
>> time-based windows
>> Thanks

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