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https://issues.apache.org/jira/browse/JCR-4674?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Julian Reschke closed JCR-4674.
-------------------------------
> Deadlock at ItemManager.getItem
> -------------------------------
>
> Key: JCR-4674
> URL: https://issues.apache.org/jira/browse/JCR-4674
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: jackrabbit-core
> Affects Versions: 2.20.0
> Reporter: Hannes Weichel
> Priority: Major
> Attachments: repository.xml
>
>
> We run a Jackrabbit in a Tomcat (8.5) system with many parallel user ( >
> 30000 parallel user ). Jackrabbit runs mostly fast and stable. But at a
> certain point of load the threads are blocking each other. Most threads are
> blocked at the following position:
> (~28000 threads all blocking):
> *org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:621)*
> (~2000 threads all blocking):
>
> *org.apache.jackrabbit.core.state.DefaultISMLocking.acquireReadLock(DefaultISMLocking.java:114)*
> Even when we block further requests, many threads keep in blocked state. We
> must hard restart tomcat and throttle user requests to get the system (very
> slow) back to a working state.
> What we tried so far to prevent this behavior (with no success):
> - configured the bundleCacheSize (see attached repository.xml )
> - configured derbyStoragePageCacheSize
> - used a JCR-Session Pool
> - adding <ISMLocking
> class="org.apache.jackrabbit.core.state.FineGrainedISMLocking"/> in
> repository.xml
> - give the system more Hardware (20 Cores, 128 GB RAM, faster Storage) - but
> hardware is not the problem.
> - fine tuned tomcat for more und faster threads
>
> *here some example StackTraces:*
>
> http-nio-8080-exec-11367
> org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:621)
>
> org.apache.jackrabbit.core.security.authorization.acl.CompiledPermissionsImpl.canRead(CompiledPermissionsImpl.java:254)
>
> org.apache.jackrabbit.core.security.DefaultAccessManager.canRead(DefaultAccessManager.java:265)
> org.apache.jackrabbit.core.ItemManager.canRead(ItemManager.java:437)
> org.apache.jackrabbit.core.ItemManager.createItemData(ItemManager.java:847)
> org.apache.jackrabbit.core.ItemManager.getItemData(ItemManager.java:391)
> org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:328)
> org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:621)
> org.apache.jackrabbit.core.NodeImpl$11.perform(NodeImpl.java:2258)
> org.apache.jackrabbit.core.NodeImpl$11.perform(NodeImpl.java:2252)
>
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
> org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
> org.apache.jackrabbit.core.NodeImpl.getProperty(NodeImpl.java:2252)
> ...
>
> http-nio-8080-exec-11352
> org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:621)
>
> org.apache.jackrabbit.core.security.authorization.acl.CompiledPermissionsImpl.canRead(CompiledPermissionsImpl.java:254)
>
> org.apache.jackrabbit.core.security.DefaultAccessManager.canRead(DefaultAccessManager.java:265)
> org.apache.jackrabbit.core.ItemManager.canRead(ItemManager.java:437)
> org.apache.jackrabbit.core.ItemManager.createItemData(ItemManager.java:847)
> org.apache.jackrabbit.core.ItemManager.getItemData(ItemManager.java:391)
> org.apache.jackrabbit.core.ItemManager.itemExists(ItemManager.java:304)
> org.apache.jackrabbit.core.ItemManager.itemExists(ItemManager.java:522)
> org.apache.jackrabbit.core.NodeImpl.hasProperty(NodeImpl.java:2460)
> ...
> http-nio-8080-exec-11382
> org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:621)
>
> org.apache.jackrabbit.core.security.authorization.acl.CompiledPermissionsImpl.canRead(CompiledPermissionsImpl.java:254)
>
> org.apache.jackrabbit.core.security.DefaultAccessManager.canRead(DefaultAccessManager.java:265)
> org.apache.jackrabbit.core.ItemManager.canRead(ItemManager.java:437)
> org.apache.jackrabbit.core.ItemManager.createItemData(ItemManager.java:847)
> org.apache.jackrabbit.core.ItemManager.getItemData(ItemManager.java:391)
> org.apache.jackrabbit.core.ItemManager.getNode(ItemManager.java:668)
> org.apache.jackrabbit.core.ItemManager.getNode(ItemManager.java:646)
>
> org.apache.jackrabbit.core.LazyItemIterator.prefetchNext(LazyItemIterator.java:120)
> org.apache.jackrabbit.core.LazyItemIterator.next(LazyItemIterator.java:257)
>
> org.apache.jackrabbit.core.LazyItemIterator.nextNode(LazyItemIterator.java:166)
> ...
> http-nio-8080-exec-11357
>
> org.apache.jackrabbit.core.state.DefaultISMLocking.acquireReadLock(DefaultISMLocking.java:114)
>
> org.apache.jackrabbit.core.state.SharedItemStateManager.acquireReadLock(SharedItemStateManager.java:1893)
>
> org.apache.jackrabbit.core.state.SharedItemStateManager.getItemState(SharedItemStateManager.java:268)
>
> org.apache.jackrabbit.core.state.LocalItemStateManager.getPropertyState(LocalItemStateManager.java:135)
>
> org.apache.jackrabbit.core.state.LocalItemStateManager.getItemState(LocalItemStateManager.java:177)
>
> org.apache.jackrabbit.core.state.XAItemStateManager.getItemState(XAItemStateManager.java:260)
>
> org.apache.jackrabbit.core.state.SessionItemStateManager.getItemState(SessionItemStateManager.java:161)
> org.apache.jackrabbit.core.ItemManager.getItemData(ItemManager.java:382)
> org.apache.jackrabbit.core.ItemManager.itemExists(ItemManager.java:304)
> org.apache.jackrabbit.core.ItemManager.itemExists(ItemManager.java:522)
> org.apache.jackrabbit.core.NodeImpl.hasProperty(NodeImpl.java:2460)
>
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