[OPENJPA-368] Multithreaded client fails randomly on EntityManager.persist() with out transaction context.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.7, 1.0.0
• Fix Version/s: 1.0.1, 1.1.0
• Component/s: jdbc
• Environment: WebLogic Server 10.0, Oracle DB
• Assignee: Unassigned
• Reporter: Vikram Bhatia
• Created: 13/Sep/07 14:04
• Updated: 09/Mar/10 18:32
• Resolved: 03/Oct/07 00:15

Description

This issue happens with the following scenario with JTA transaction.

Suppose there is Entity A which is related to table with two columns accountId and name. accountId is PK of the table whose value is generated using sequence in DB.

1. Thread A starts Transaction 1.
2. Thread B starts Transaction 2.
3. Thread A and Thread B both calls EntityManager.persist(o) where o is
Entity object whose primary key is generated with a sequence in DB.
4. A call is made to o.getAccountId() concurrently.
5. Thread A suspends Transaction 1, and gets the value of accountId. It updates
sequence value in DB with new Transaction 3. It saves Transaction 1.
6. Thread B suspends Transaction 2, and gets the value of accountId. It updates
sequence value in DB with new Transaction 4. It saves Transaction 2.
7. Now, when both Thread A and Thread B resumes outer transaction
concurrently, it updates Transaction Manager with Transaction 2.

The problem happens when JTA transaction is saved in AbstractJDBCSeq _outerTransaction variable. The variable gets overwritten if multiple threads load the value of accountId from sequence in DB, when it resumes the JTA transaction later it resumes the transaction 2 for both threads resulting in following exception.

javax.ejb.EJBException: nested exception is: javax.persistence.TransactionRequiredException: The method public abstract void javax.persistence.EntityManager.persist(java.lang.Object) must be called in the context of a transaction.
javax.persistence.TransactionRequiredException: The method public abstract void javax.persistence.EntityManager.persist(java.lang.Object) must be called in the context of a transaction.
at weblogic.deployment.BasePersistenceContextProxyImpl.validateInvocation(BasePersistenceContextProxyImpl.java:121)
at weblogic.deployment.BasePersistenceContextProxyImpl.invoke(BasePersistenceContextProxyImpl.java:86)
at weblogic.deployment.TransactionalEntityManagerProxyImpl.invoke(TransactionalEntityManagerProxyImpl.java:90)
at weblogic.deployment.BasePersistenceContextProxyImpl.invoke(BasePersistenceContextProxyImpl.java:80)
at $Proxy63.persist(Unknown Source)

Please check README.txt of attached testcase.zip to see how to reproduce the issue.