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https://issues.apache.org/jira/browse/DERBY-6879?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15347036#comment-15347036
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Brett Bergquist commented on DERBY-6879:
----------------------------------------
I am questioning if this is the final correct answer. In this one case, the
cleanUpOnError is being called by connection that is executing a statement so
the locking is connection and then XATransactionState. When a timeout occurs,
the locking is XATransactionState and then the connection. When both occur at
the same time the deadlock occurs. My proposed fix handles this situation.
There is other possibilities. So for example, code calls XAResource.commit.
This has the locking pattern of XATransactionState and then connection. So
if the timeout were to occur during this time, then there would not be a
deadlock here because the proposed solution is going to lock the connection and
then the XATransacttionState.
The original deadlock problem can only occur if the
XATransactionState.cleanupOnError is called while the connection is locked and
executing and a cleanup needs to be performed.
> Engine deadlock between XA timeout handling and cleanupOnError
> --------------------------------------------------------------
>
> Key: DERBY-6879
> URL: https://issues.apache.org/jira/browse/DERBY-6879
> Project: Derby
> Issue Type: Bug
> Components: Services
> Affects Versions: 10.10.2.0
> Environment: Solaris 10.5 on Oracle M5000
> Reporter: Brett Bergquist
>
> Deadlock between XA timer cleanup task and the ContextManager.cleanupOnError
> Found one Java-level deadlock:
> =============================
> "DRDAConnThread_34":
> waiting to lock monitor 0x0000000104b14d18 (object 0xfffffffd9090f058, a
> org.apache.derby.jdbc.XATransactionState),
> which is held by "Timer-0"
> "Timer-0":
> waiting to lock monitor 0x00000001038b96e8 (object 0xfffffffd9090d8b0, a
> org.apache.derby.impl.jdbc.EmbedConnection40),
> which is held by "DRDAConnThread_34"
>
> Java stack information for the threads listed above:
> ===================================================
> "DRDAConnThread_34":
> at org.apache.derby.jdbc.XATransactionState.cleanupOnError(Unknown
> Source)
> - waiting to lock <0xfffffffd9090f058> (a
> org.apache.derby.jdbc.XATransactionState)
> at
> org.apache.derby.iapi.services.context.ContextManager.cleanupOnError(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.cleanupOnError(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(Unknown
> Source)
> - locked <0xfffffffd9090d8b0> (a
> org.apache.derby.impl.jdbc.EmbedConnection40)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement.execute(Unknown
> Source)
> at org.apache.derby.iapi.jdbc.BrokeredPreparedStatement.execute(Unknown
> Source)
> at org.apache.derby.impl.drda.DRDAStatement.execute(Unknown Source)
> at
> org.apache.derby.impl.drda.DRDAConnThread.parseEXCSQLSTTobjects(Unknown
> Source)
> at org.apache.derby.impl.drda.DRDAConnThread.parseEXCSQLSTT(Unknown
> Source)
> at org.apache.derby.impl.drda.DRDAConnThread.processCommands(Unknown
> Source)
> at org.apache.derby.impl.drda.DRDAConnThread.run(Unknown Source)
> "Timer-0":
> at org.apache.derby.impl.jdbc.EmbedConnection.xa_rollback(Unknown Source)
> - waiting to lock <0xfffffffd9090d8b0> (a
> org.apache.derby.impl.jdbc.EmbedConnection40)
> at org.apache.derby.jdbc.XATransactionState.cancel(Unknown Source)
> - locked <0xfffffffd9090f058> (a
> org.apache.derby.jdbc.XATransactionState)
> at
> org.apache.derby.jdbc.XATransactionState$CancelXATransactionTask.run(Unknown
> Source)
> at java.util.TimerThread.mainLoop(Timer.java:555)
> at java.util.TimerThread.run(Timer.java:505)
>
> Found 1 deadlock.
> This deadlock caused Derby to create 18000 transaction recovery logs because
> of the XA transaction that did not cleanup in the timeout. Rebooting the
> system would cause a 50 hour boot up time to process the transaction logs so
> recovery had to be done by going to a backup database before the issue
> occurred.
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