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https://issues.apache.org/jira/browse/HIVE-22420?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16966673#comment-16966673
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Aron Hamvas commented on HIVE-22420:
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Thanks for the review, [~pvary]! The requested change is in patch 2. If ok, can
you commit this change for me?
> DbTxnManager.stopHeartbeat() should be thread-safe
> --------------------------------------------------
>
> Key: HIVE-22420
> URL: https://issues.apache.org/jira/browse/HIVE-22420
> Project: Hive
> Issue Type: Bug
> Affects Versions: 3.1.0
> Reporter: Aron Hamvas
> Assignee: Aron Hamvas
> Priority: Major
> Attachments: HIVE-22420.1.patch, HIVE-22420.2.patch
>
>
> When a transactional query is being executed and interrupted via HS2 close
> operation request, both the background pool thread executing the query and
> the HttpHandler thread running the close operation logic will eventually call
> the below method:
> {noformat}
> Driver.releaseLocksAndCommitOrRollback(commit boolean)
> {noformat}
> Since this method is invoked several times in both threads, it can happen
> that the two threads invoke it at the same time, and due to a race condition,
> the txnId field of the DbTxnManager used by both threads could be set to 0
> without actually successfully aborting the transaction.
> The root cause is stopHeartbeat() method in DbTxnManager not being thread
> safe:
> When Thread-1 and Thread-2 enter stopHeartbeat() with very little time
> difference, Thread-1 might successfully cancel the heartbeat task and set the
> heartbeatTask field to null, while Thread-2 is trying to observe its state.
> Thread-1 will return to the calling rollbackTxn() method and continue
> execution there, while Thread-2 wis thrown back to the same method with a
> NullPointerException. Thread-2 will then set txnId to 0, and Thread-1 is
> sending this 0 value to HMS. So, the txn will not be aborted, and the locks
> cannot be released later on either.
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