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https://issues.apache.org/jira/browse/JCR-3226?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14622347#comment-14622347
]
Thomas Mueller commented on JCR-3226:
-------------------------------------
So the output of the test is for example:
i: 0
i: 1
...
i: 40
i: 41
and then it stops there and doesn't continue. If it doesn't continue for a few
seconds, it was always a deadlock, and I think always the same type of
deadlock. "jstack -l <pid>", or pausing in Eclipse will show that.
Some observation below. I don't currently understand the algorithm that is
used, how this is supposed to work, so I can't say if some state is a
localState (or transient) while it should not longer be one, or before it
should be one, or if there is a problem with the overall algorithm.
{noformat}
NodeState #241:
isTransient = false
overlayedState = #247
status = 1
propertyNames = primaryType
NodeState #242:
isTransient = true
listener = SessionItemStateManager #260
overlayedState = #241
status = 2
propertyNames = primaryType, x
Java stack information for the threads listed above:
===================================================
"Thread-179":
* the sessions SessionItemStateManager is #260
* locked the transient.overlayedState, which is called "localState" here,
and waits to lock the transient
at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:153)
- waiting to lock <7f42b1b10> (a
org.apache.jackrabbit.core.state.NodeState) #242
- locked <7f42b0000> (a org.apache.jackrabbit.core.state.NodeState) #241
at
org.apache.jackrabbit.core.state.SessionItemStateManager.makePersistent(SessionItemStateManager.java:984)
- locked <7f42b0000> (a org.apache.jackrabbit.core.state.NodeState) #241
at org.apache.jackrabbit.core.NodeImpl.makePersistent(NodeImpl.java:867)
at
org.apache.jackrabbit.core.ItemSaveOperation.persistTransientItems(ItemSaveOperation.java:849)
at
org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:243)
at
org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
at
org.apache.jackrabbit.core.session.SessionSaveOperation.perform(SessionSaveOperation.java:65)
at
org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
at org.apache.jackrabbit.core.SessionImpl.perform(SessionImpl.java:361)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:812)
at
org.apache.jackrabbit.core.deadlock.RandomChange.randomOp(RandomChange.java:96)
at
org.apache.jackrabbit.core.deadlock.RandomChange$1.run(RandomChange.java:58)
"Thread-180":
* the sessions SessionItemStateManager is #283
* locked the transient of the other session, and waits to lock the
transient.overlayedState
at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:153)
- waiting to lock <7f42b0000> (a
org.apache.jackrabbit.core.state.NodeState) #241
- locked <7f42b1b10> (a org.apache.jackrabbit.core.state.NodeState) #242
at org.apache.jackrabbit.core.state.ItemState.pull(ItemState.java:152)
- locked <7f42b1b10> (a org.apache.jackrabbit.core.state.NodeState) #242
at
org.apache.jackrabbit.core.state.SessionItemStateManager.stateCreated(SessionItemStateManager.java:788)
at
org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
at
org.apache.jackrabbit.core.state.LocalItemStateManager.stateCreated(LocalItemStateManager.java:487)
at
org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.stateCreated(SharedItemStateManager.java:407)
at
org.apache.jackrabbit.core.state.ItemState.notifyStateCreated(ItemState.java:233)
at
org.apache.jackrabbit.core.state.ChangeLog.persisted(ChangeLog.java:323)
at
org.apache.jackrabbit.core.state.SharedItemStateManager$Update.end(SharedItemStateManager.java:831)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:1541)
at
org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:400)
at
org.apache.jackrabbit.core.state.XAItemStateManager.update(XAItemStateManager.java:354)
at
org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:375)
at
org.apache.jackrabbit.core.state.SessionItemStateManager.update(SessionItemStateManager.java:275)
at
org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:258)
at
org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
at
org.apache.jackrabbit.core.session.SessionSaveOperation.perform(SessionSaveOperation.java:65)
at
org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
at org.apache.jackrabbit.core.SessionImpl.perform(SessionImpl.java:361)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:812)
at
org.apache.jackrabbit.core.deadlock.RandomChange.randomOp(RandomChange.java:96)
at
org.apache.jackrabbit.core.deadlock.RandomChange$1.run(RandomChange.java:58)
{noformat}
> stateCreated deadlock
> ---------------------
>
> Key: JCR-3226
> URL: https://issues.apache.org/jira/browse/JCR-3226
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: jackrabbit-core
> Affects Versions: 2.2, 2.4
> Reporter: Jukka Zitting
> Assignee: Jukka Zitting
> Labels: deadlock
> Attachments: JCR-3226-test.patch
>
>
> In JCR-2650 a potential deadlock in SessionItemStateManager.stateModified()
> got fixed by postponing the work to the save() call.
> Unfortunately this still leaves the stateCreated() method vulnerable to a
> similar (though much less likely) deadlock scenario (observed in Jackrabbit
> 2.2.x):
> Thread A:
> at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:118)
> - waiting to lock <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> - locked <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> at org.apache.jackrabbit.core.state.ItemState.pull(ItemState.java:152)
> - locked <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> at
> org.apache.jackrabbit.core.state.SessionItemStateManager.stateCreated(SessionItemStateManager.java:791)
> at
> org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.stateCreated(LocalItemStateManager.java:428)
> at
> org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager.stateCreated(SharedItemStateManager.java:398)
> at
> org.apache.jackrabbit.core.state.ItemState.notifyStateCreated(ItemState.java:231)
> at
> org.apache.jackrabbit.core.state.ChangeLog.persisted(ChangeLog.java:309)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager$Update.end(SharedItemStateManager.java:777)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:1488)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:351)
> at
> org.apache.jackrabbit.core.state.XAItemStateManager.update(XAItemStateManager.java:354)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:326)
> at
> org.apache.jackrabbit.core.state.SessionItemStateManager.update(SessionItemStateManager.java:289)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:258)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
> at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
> Thread B:
> at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:119)
> - waiting to lock <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> - locked <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> at org.apache.jackrabbit.core.NodeImpl.makePersistent(NodeImpl.java:869)
> - locked <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.persistTransientItems(ItemSaveOperation.java:836)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:243)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
> at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
> at
> org.apache.jackrabbit.core.session.SessionSaveOperation.perform(SessionSaveOperation.java:42)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.SessionImpl.perform(SessionImpl.java:355)
> at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:758)
> IIUC this can only occur when two sessions are concurrently importing a node
> with the same UUID.
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