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https://issues.apache.org/jira/browse/FLINK-37416?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-37416:
-----------------------------------
Labels: pull-request-available (was: )
> DDB Streams connector flink state inconsistency issue
> -----------------------------------------------------
>
> Key: FLINK-37416
> URL: https://issues.apache.org/jira/browse/FLINK-37416
> Project: Flink
> Issue Type: Bug
> Components: Connectors / DynamoDB
> Environment: This is a flink environment created using EKS cluster
> with Karpenter autoscaler
> Reporter: Abhi Gupta
> Priority: Major
> Labels: pull-request-available
>
> We found that for a customer when there are multiple restarts, there are
> state inconsistency issues between the job manager and the task manager.
> There is a shard which is in ASSIGNED state in the JobManager, but that shard
> is not even present in the TaskManager state. Here is a rough timeline of the
> two events:
> h2. Instance-1
> There are 4 task managers as seen from the logs
> The data loss started at around {{{}2025-01-07 13:51:30.094{}}}. Job
> restarted from checkpoint 2 at around 13:39
>
> * Task cancellation triggered at: {{2025-01-07 13:38:34.024}}
> * Task got cancelled at: {{2025-01-07 13:38:34.626}}
> * Task restarted at: {{2025-01-07 13:39:26.657}} (Start time of the job from
> scratch after removing the savepoint) no checkpoint used to restore the job
> * Another cancellation triggered at: {{2025-01-07 13:52:21.386}}
> * Cancellation completed at: {{{}2025-01-07 13:52:21.976{}}}. Job restarted
> from checkpoint 2
> * Another cancellation triggered at: {{2025-01-07 15:36:55.472}}
> * This cancellation completed at: {{{}2025-01-07 15:36:57.627{}}}. Job
> restarted from checkpoint 106
> * Another cancellation triggered at: {{2025-01-07 16:43:17.177}}
> * This cancellation completed at: {{{}2025-01-07 16:43:17.661{}}}. Job
> restarted from checkpoint 172
> * Another cancellation: {{2025-01-07 17:49:33.387}}
> * This cancellation completed at: {{2025-01-07 17:49:34.117}}
> Checkpoint completion times. These are taken using the following log:
> Committing
> buffer-money-movements-docstore-all-protos/95b40845f9d7ccf0dfbe8eeb58830194/chk-172/_metadata
> with MPU ID xxx
> |Checkpoint|Time finished|
> |2|2025-01-07T13:51:31.500|
> |106|2025-01-07T15:36:07.984|
> |172|2025-01-07T16:42:25.420|
> |238|2025-01-07T17:49:25.897|
> Shards which have state consistency issue per operator:
> {{d9142698e8c34a850f718000f27c06f1: [shardId-00000001736149119171-7fe92d34]}}
> {{Missing splits in 464d94ba07e08db815bc2c93bc566b1a:
> [shardId-00000001736148094601-d38142b5]}}
> {{Missing splits in e5540dfffda9a53d8430f30b2d41f1b4:
> [shardId-00000001736150901519-43bc576d]}}
> Assignment times of those shards to the readers:
> * 2025-01-07T13:51:30.094 ({{{}shardId-00000001736149119171-7fe92d34{}}})
> * Never assigned ({{{}shardId-00000001736148094601-d38142b5{}}})
> * 2025-01-07T13:51:30.095 ({{{}shardId-00000001736150901519-43bc576d{}}})
>
> h2. Instance-2
> * Attempt to cancel some tasks at {{2025-02-14T20:04:35.840667Z}}
> * At {{2025-02-14T20:04:36.166849Z}} the TM-1-8 finally say that the JOB has
> been cancelled and they have sent job cancellation event to the JM, but
> seemingly there is no cancellation event in the JM logs
> * Again, at {{{}2025-02-14T20:05:46.940638Z{}}}, the TM-1-8 try to cancel
> the job
> * At {{{}2025-02-14T20:05:47.151611Z{}}}, TM-1-8 completes cancellation of
> the job and sends cancellation message to JM but again, the JM has never
> received a cancellation event of the job
> * Job restore from savepoint 14: {{2025-02-14T20:14:34.814526406Z}}
> We see that at around {{2025-02-14T20:05:46.084798Z}} the child shard stopped
> getting polled, so this might be the time when the state got corrupted
>
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