[GitHub] flink pull request: [FLINK-3109]Join two streams with two differen...

[StephanEwen <gi...@git.apache.org>]

Github user StephanEwen commented on the pull request:

    https://github.com/apache/flink/pull/1527#issuecomment-181922703
  
    @wangyangjun We actually merged all the changes concerning the state abstraction.
    
    To make this window join work seamlessly on Flink's state backends (memory, or key/value stores, managed memory, ...) you would need to implement it against the key/value state. That means that whenever you store data in the operator, the data should go into the partitioned state that you can obtain from the `AbstractStreamOperator` or the `RuntimeContext`.
    
    I think that for this window operator, the `ListState` is a good choice, where you can add values to a key and retrieve the list as a whole once the windows are evaluated.
    
    Please write back if you need some more pointers on the state abstraction.



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