[GitHub] flink issue #1690: FLINK-3398: Allow for opting-out from Kafka offset auto-c...

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

Github user tzulitai commented on the issue:

    https://github.com/apache/flink/pull/1690
  
    What's the status of this PR? I think it is a good functionality to add. @shikhar if you'd like to continue working on this, I'm happy to help shepherd this PR for merging.
    
    Some of my input from the previous discussions on the interpretation of "auto.commit.enable":
    I agree with @rmetzger that stretching the definition of this config to "on checkpoint or periodically" isn't a good idea. Committing the offsets back to Kafka on 'notifyCheckpointComplete()' is a Flink-specific behaviour. I think mixing Flink-specific behaviour within Kafka original configs can be confusing for frequent Kafka users and difficult to maintain in the long run.
    
    Perhaps we can have something like "flink.commit-on-checkpoint". What I have in mind:
    > // commit to ZK / broker only on Flink's checkpoint.
    > flink.commit-on-checkpoint=true auto.commit.enable=*
    >
    > // periodically commits to ZK / broker
    > flink.commit-on-checkpoint=false auto.commit.enable=true
    >
    > // no commit to ZK / broker at all
    > flink.commit-on-checkpoint=false auto.commit.enable=false
    
    The first option will be valid only when checkpointing is enabled also. Otherwise, whether or not checkpointing is enabled does not effect the above settings.
    
    I think this better matches the idea that "the Kafka offset store is only used for exposure of progress to the outside world, and not for recovery / manipulation of how Flink reads from Kafka".


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