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https://issues.apache.org/jira/browse/ARIES-1083?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christian Schneider resolved ARIES-1083.
----------------------------------------
Resolution: Fixed
Assignee: Christian Schneider
Fix Version/s: jpa-2.0.0
In Aries JPA 2 the EntityManagers are stored per thread now. So this should not
happen anymore.
> Create either a synchronised entity manager or a proxy which creates an
> entity manager for each request
> -------------------------------------------------------------------------------------------------------
>
> Key: ARIES-1083
> URL: https://issues.apache.org/jira/browse/ARIES-1083
> Project: Aries
> Issue Type: Improvement
> Components: JPA
> Affects Versions: jpa-container-context-1.0.1
> Reporter: Joe Qiang Luo
> Assignee: Christian Schneider
> Fix For: jpa-2.0.0
>
>
> When using Apache Aries (container managed Transactions, JTA) with Hibernate
> for persistence, if we start multiple threads to read from the database
> without transactions (Transaction Annotation is ommited), we get the
> following stacktrace:
> org.hibernate.AssertionFailure: possible non-threadsafe access to the session
> at
> org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:130)
>
> at
> org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1103)
>
> at org.hibernate.loader.Loader.processResultSet(Loader.java:960)
> at org.hibernate.loader.Loader.doQuery(Loader.java:910)
> at
> org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341)
>
> at org.hibernate.loader.Loader.doList(Loader.java:2516)
> at org.hibernate.loader.Loader.doList(Loader.java:2502)
> at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2332)
> at org.hibernate.loader.Loader.list(Loader.java:2327)
> at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:490)
> at
> org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:355)
>
> at
> org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:195)
>
> at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1247)
> at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
> The reason we got this exception in a non-transacted mode is that we inject
> EntityManager in our implementation and use it for different requests from
> multiple threads. Unfortunately, the EntityManager is not thread safe and we
> have to refactor the code to inject EntityManagerFactory instead since
> EntityManagerFactory is thread safe and then create EntityManagers in each
> method programmatically.
> From Aries stand point, we should be able to improve it in order to ease the
> pain by creating a synchronized entity manager, or a proxy which creates
> entity managers for each request. And the proxy would probably do the
> following:
> 1. create EntityManager;
> 2. perform request;
> 3. close EntityManager;
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