[
https://issues.apache.org/jira/browse/JCR-3738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13916455#comment-13916455
]
Jukka Zitting commented on JCR-3738:
------------------------------------
The key threads here seem to be (with non-essential stack frames excluded):
"pool-7-thread-2-Granite Workflow External Process Job
Queue(com/adobe/granite/workflow/external/job/etc/workflow/models/dam/update_asset/jcr_content/model)"
daemon prio=10 tid=0x00007f12a46bf800 nid=0x2712 in Object.wait()
[0x00007f125b4bf000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000b4151370> (a
org.apache.jackrabbit.core.state.DefaultISMLocking)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.acquireWriteLock(SharedItemStateManager.java:1898)
at
org.apache.jackrabbit.core.state.SharedItemStateManager$Update.begin(SharedItemStateManager.java:579)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.beginUpdate(SharedItemStateManager.java:1507)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:1537)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:812)
"pool-7-thread-1" daemon prio=10 tid=0x00007f12a46ea800 nid=0x2711 runnable
[0x00007f12631b1000]
java.lang.Thread.State: RUNNABLE
at com.ibm.db2.jcc.am.qo.execute(qo.java:2724)
- locked <0x00000000ba4b7e30> (a com.ibm.db2.jcc.t4.b)
at
org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
at
org.apache.jackrabbit.core.util.db.ConnectionHelper.exec(ConnectionHelper.java:288)
at
org.apache.jackrabbit.core.journal.DatabaseJournal$DatabaseRevision.set(DatabaseJournal.java:834)
- locked <0x00000000b41afb40> (a
org.apache.jackrabbit.core.journal.DatabaseJournal$DatabaseRevision)
at
org.apache.jackrabbit.core.cluster.ClusterNode.setRevision(ClusterNode.java:872)
at
org.apache.jackrabbit.core.cluster.ClusterNode$WorkspaceUpdateChannel.updateCommitted(ClusterNode.java:703)
at
org.apache.jackrabbit.core.state.SharedItemStateManager$Update.end(SharedItemStateManager.java:845)
at
org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:1537)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:812)
It looks like the first thread managed to acquire the cluster lock in the
database as that's done before the Java-level acquireWriteLock() call. But the
second thread was already inside that critical section (or somehow managed to
enter it afterwards), and now isn't able to complete the transaction because
the database won't allow it.
I'll look into this in more detail next week.
> CLONE - Deadlock on LOCAL_REVISION table in clustering environment
> ------------------------------------------------------------------
>
> Key: JCR-3738
> URL: https://issues.apache.org/jira/browse/JCR-3738
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: clustering
> Affects Versions: 2.6.2
> Environment: CQ5.6.1 with jackrabbit-core 2.6.2 backed off ibm db2
> v10.5
> Reporter: Ankush Malhotra
> Assignee: Jukka Zitting
> Priority: Critical
> Attachments: db-deadlock-info.txt, stat-cache.log, threaddumps.zip
>
>
> Original, cloned description:
> > When inserting a lot of nodes concurrently (100/200 threads) the system
> > hangs generating a deadlock on the LOCAL_REVISION table.
> > There is a thread that starts a transaction but the transaction remains
> > open, while another thread tries to acquire the lock on the table.
> > This actually happen even if there is only a server up but configured in
> > cluster mode.
> > I found that in AbstractJournal, we try to write the LOCAL_REVISION even if
> > we don't sync any record because they're generated by the same journal of
> > the thread running.
> >
> > Removing this unnecessary (to me :-) ) write to the LOCAL_REVISION table,
> > remove the deadlock.
> This might not be the exact same case with this issue. See the attached
> thread dumps etc. for full details.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
