Hi, To expand on Fabian's answer, there's a few API for join.
* connect - you have to provide a CoprocessFunction. * window join/cogroup - you provide key selector functions, a time window and a join/cogroup function. With the first method, you have to write more code, in exchange for much more flexible join condition. Regards, Kien On Jul 20, 2017, 01:55, at 01:55, Fabian Hueske <fhue...@gmail.com> wrote: >Hi, > >there are basically two operations to merge streams. > >1. Union simply merges the input streams such that the resulting stream >has >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. >Join >usually needs to be manually implemented using a stateful >CoProcessFunction. > >Once the streams are unioned or joined, you can apply a time-window on >the >result stream. > >Best, Fabian > >2017-07-19 9:05 GMT+02:00 Jone Zhang <joyoungzh...@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 >>
