0 Replies Latest reply on Jan 10, 2008 10:25 AM by mazz

    hibernate clearing too much in 2nd-level cache w/native quer

    mazz Master

      I'm seeing some interesting things happening with hibernate's second level cache when using native queries in my EJB3/JPA app and was wondering if someone can verify that "this is the way it is supposed to work" and more importantly how can I work around it :)

      I have a multi-threaded system where I am doing concurrent database access; in one of those threads, I am in a transaction (call it T1) and the database access involves executing a native query (a native INSERT query to be exact) via entityManager.createNativeQuery(...).executeUpdate().

      At the same time, in another set of threads, I'm hammering the database with other queries - nothing fancy, and no native queries.

      Those other threads end up slowing down the system and the thread running in T1 is slowed down. So much so that more than 15 seconds go by after T1 is started but before I executeUpdate that native query.

      The native query then bombs out with a failure; here's part of the log that shows the problem, stripped of everything not important:

      18:52:42 INFO ...enter T1...
      ....
      18:52:57 INFO ...Caused by: javax.persistence.PersistenceException: org.hibernate.cache.CacheException: org.jboss.cache.lock.TimeoutException: failure acquiring lock: fqn=/on_ear,jonpu/org/jboss/on/domain/resource/ResourceType,
      


      Look at the timestamps - 18:52.42 plus 15 seconds is 18:52.57
      we are hitting a cache timeout before we can complete the native query. The cache timeout is 15s based on the exception message I see later in the logs "Caused by: org.jboss.cache.lock.TimeoutException: write lock for /on_ear,jonpu/org/jboss/on/domain/resource/ResourceType could not be acquired after 15000 ms"

      The odd thing is, this native query does not directly involve the entity referred to in this error message (ResourceType). So, I asked myself, "why is hibernate trying to get a write lock for this entity in its second-level cache?" The ResourceType entity is annotated with "@org.hibernate.annotations.Cache(usage= CacheConcurrencyStrategy.TRANSACTIONAL)" and we are using JBossCache.

      Looking at the stack trace of the exception, I then saw this:

      at org.jboss.ejb3.entity.JBCCache.clear(JBCCache.java:207)
      at org.hibernate.cache.TransactionalCache.clear(TransactionalCache.java:124)
      at org.hibernate.impl.SessionFactoryImpl.evictEntity(SessionFactoryImpl.java:832)
      at org.hibernate.action.BulkOperationCleanupAction.evictEntityRegions(BulkOperationCleanupAction.java:137)
      at org.hibernate.action.BulkOperationCleanupAction.init(BulkOperationCleanupAction.java:100)
      at org.hibernate.engine.query.NativeSQLQueryPlan.coordinateSharedCacheCleanup(NativeSQLQueryPlan.java:134)
      at org.hibernate.engine.query.NativeSQLQueryPlan.performExecuteUpdate(NativeSQLQueryPlan.java:144)
      


      It looks like hibernate is trying to perform some cache clearing with the bulk native query execution and trying to invalidate too much.

      What ways are there to turn off or adjust this behavior? I don't want to extend the 15s time limit since I can't guarantee what's a long enough time and what should truly be considered a timeout.