[jira] [Created] (FLINK-4080) Kinesis consumer not exactly-once if stopped in the middle of processing aggregated records

[Shang Yuanchun (Jira)]

Tzu-Li (Gordon) Tai created FLINK-4080:
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             Summary: Kinesis consumer not exactly-once if stopped in the middle of processing aggregated records
                 Key: FLINK-4080
                 URL: https://issues.apache.org/jira/browse/FLINK-4080
             Project: Flink
          Issue Type: Sub-task
          Components: Kinesis Connector, Streaming Connectors
            Reporter: Tzu-Li (Gordon) Tai
            Assignee: Tzu-Li (Gordon) Tai
            Priority: Critical
             Fix For: 1.1.0


I've occasionally experienced unsuccessful ManualExactlyOnceTest after several tries.

Kinesis records of the same aggregated batch will have the same sequence number, and different sub-sequence numbers (http://docs.aws.amazon.com/streams/latest/dev/kinesis-kpl-consumer-deaggregation.html). The current state of the consumer is committing state every time it finishes processing a record, even de-aggregated ones. This is a bug since this will incorrectly mark all remaining records of the de-aggregated batch as processed in the state.

Proposed fix: Use the extended `UserRecord` class in KCL to represent all records (either non- or de-aggregated) instead of the basic `Record` class. This gives access to whether or not the record was originally aggregated. If we encounter a de-aggregated record, don't update state until we finished processing the last record of the batch.



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