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https://issues.apache.org/jira/browse/OPENJPA-1716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13422512#comment-13422512
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Scott Parkerson commented on OPENJPA-1716:
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I, too, have run into this problem when trying to use a container-managed JPA
persistence context in Apache Servicemix (Fusesource Fuse ESB). The problem
occurs when using Apache Aries Blueprint JPA / JTA which creates the
EntityManagerFactory for the persistence unit at bundle start, and then injects
an EntityManager into each DAO that I create that is part of the persistence
unit. Those DAOs are exposed as OSGi services to business services, which are
then called by webservices, Camel routes, etc.
Everything is fine until two or more threads hit an EntityManager; at that
point, we get the warning to try openjpa.Multithreaded=true. Adding that to my
Persistence Context configuration causes the aforementioned deadlock (same
trace and everything).
If changing the applications is required to work around this without a patch,
then can you recommend a way to do this using the container to manage
persistence?
> Deadlock with openjpa.Multithreaded=true
> ----------------------------------------
>
> Key: OPENJPA-1716
> URL: https://issues.apache.org/jira/browse/OPENJPA-1716
> Project: OpenJPA
> Issue Type: Bug
> Affects Versions: 2.0.0-M1, 2.0.0-M2, 2.0.0-M3, 2.0.0-beta, 2.0.0-beta2,
> 2.0.0-beta3, 2.0.0
> Reporter: Stefan Wokusch
> Assignee: Rick Curtis
> Attachments: OPENJPA-1716.PATCH
>
>
> There is a Deadlock by using Multithreaded=true and work with some Threads on
> the same Entitymanager.
> After many hours of debugging, i found a solution for that Deadlock: The
> Problem could be solved by adding another lock into the lock Method of the
> StateManagerImpl:
> StateManagerImpl ~line3308
> /**
> * Lock the state manager if the multithreaded option is set.
> */
> protected void lock() {
> if (_instanceLock != null){
> _broker.lock();//<- This is the new Part to fix the Deadlock
> _instanceLock.lock();
> }
> }
> Worked for me without Problems for a long time.
> Some other Configurations:
> <persistence xmlns="http://java.sun.com/xml/ns/persistence";
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; version="1.0">
> <persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
> <mapping-file>orm.xml</mapping-file>
>
> <class>...</class>
> <class>...</class>
>
> <properties>
> <property name="openjpa.OrphanedKeyAction"
> value="log(Channel=Orphans, Level=TRACE)" />
> <property name="openjpa.ConnectionFactoryProperties"
> value="PrettyPrint=true, PrettyPrintLineLength=80" />
> <property name="openjpa.Multithreaded" value="true" />
> <property name="openjpa.InverseManager" value="true" />
> <property name="openjpa.LockManager" value="none" />
> <property name="openjpa.WriteLockLevel" value="none" />
> <property name="openjpa.Compatibility" value="
> QuotedNumbersInQueries=true,
> CopyOnDetach=true,
> cascadeWithDetach=true,
>
> superclassDiscriminatorStrategyByDefault=false
> " />
> <property name="openjpa.DetachState"
> value="fetch-groups" />
> <property name="openjpa.jdbc.SynchronizeMappings"
> value="buildSchema" />
> <!-- Default DataSource -->
> <property name="openjpa.ConnectionURL"
> value="jdbc:h2:db/test" />
> <property name="openjpa.ConnectionDriverName"
> value="org.h2.Driver" />
> </properties>
> </persistence-unit>
> </persistence>
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