[jira] [Commented] (FLINK-12296) Data loss silently in RocksDBStateBackend when more than one operator(has states) chained in a single task

["Yu Li (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-12296?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16823988#comment-16823988 ] 

Yu Li commented on FLINK-12296:
-------------------------------

Thanks for filing the JIRA [~klion26]. Is this some regression issue or long existing one? Please fill the affected version field after confirmation. And since data loss is a critical issue, I'd suggest to escalate the priority from Major to Critical. Thanks.

> Data loss silently in RocksDBStateBackend when more than one operator(has states) chained in a single task 
> -----------------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-12296
>                 URL: https://issues.apache.org/jira/browse/FLINK-12296
>             Project: Flink
>          Issue Type: Bug
>          Components: Runtime / State Backends
>            Reporter: Congxian Qiu(klion26)
>            Assignee: Congxian Qiu(klion26)
>            Priority: Major
>
> As the mail list said[1], there may be a problem when more than one operator chained in a single task, and all the operators have states, we'll encounter data loss silently problem.
> Currently, the local directory we used is like below
> ../local_state_root_1/allocation_id/job_id/vertex_id_subtask_idx/chk_1/(state),
>  
> if more than one operator chained in a single task, and all the operators have states, then all the operators will share the same local directory(because the vertext_id is the same), this will lead a data loss problem. 
>  
> The path generation logic is below:
> {code:java}
> // LocalRecoveryDirectoryProviderImpl.java
> @Override
> public File subtaskSpecificCheckpointDirectory(long checkpointId) {
>    return new File(subtaskBaseDirectory(checkpointId), checkpointDirString(checkpointId));
> }
> @VisibleForTesting
> String subtaskDirString() {
>    return Paths.get("jid_" + jobID, "vtx_" + jobVertexID + "_sti_" + subtaskIndex).toString();
> }
> @VisibleForTesting
> String checkpointDirString(long checkpointId) {
>    return "chk_" + checkpointId;
> }
> {code}
> [1] [https://app.smartmailcloud.com/web-share/MDkE4DArUT2eoSv86xq772I1HDgMNTVhLEmsnbQ7]



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