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https://issues.apache.org/jira/browse/FLINK-4080?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Metzger resolved FLINK-4080.
-----------------------------------
Resolution: Fixed
Resolved in http://git-wip-us.apache.org/repos/asf/flink/commit/fa42cdab
> 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 code 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:
> 1. 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.
> 2. The sequence number state we are checkpointing needs to be able to
> indicate that the last seen sequence number of a shard may be a de-aggregated
> shard, i.e., {"shard0" -> "5:8", "shard1" -> "2"} meaning the 8th sub-record
> of the 5th record was last seen for shard 0. On restore, we start again from
> record 5 for shard 0 and skip the first 7 sub-records; however, for shard 1
> we start from record 3 since record 2 is non-aggregated and already fully
> processed.
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