[GitHub] flink pull request: User defined communication between parallel in...

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

Github user fhueske commented on the pull request:

    https://github.com/apache/flink/pull/975#issuecomment-127405822
  
    Hi @sachingoel0101,
    
    allowing tasks to communicate with each other over side-connections breaks the current assumptions that TMs exchange data only over data connections and control communication is only happening between JM and TM. By allowing parallel tasks to exchange data, these tasks are no longer independent. In fact the system relies on these assumptions at several places including fault tolerance & recovery. Even if in your use case, exact recovery might not be important, other users might use this feature in a different way.
    
    Changes that have the potential to change the behavior of the system like this PR need to be discussed in detail by the Flink community. This can be done by opening a JIRA and adding an initial design sketch or proposing such changes on the mailing list and asking for detailed feedback.
    
    I don't think we can merge this into Flink without breaking the system at several places.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---