[hibernate-issues] [Hibernate-JIRA] Created: (HSEARCH-961) ObjectNotFoundException not caught in FullTextSession for deleted objects

[Anders Soee (JIRA)]

ObjectNotFoundException not caught in FullTextSession for deleted objects
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                 Key: HSEARCH-961
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HSEARCH-961
             Project: Hibernate Search
          Issue Type: Bug
          Components: query
    Affects Versions: 3.4.1.Final
         Environment: Hibernate 3.6.7
EHCache 1.2.4 and 2.4.6 in Read-write mode.
MS SQL Server 2000
async indexing.
            Reporter: Anders Soee
            Priority: Minor


Experienced behavior:
1: Show page with search results.
2: Delete one
3: Redirect back to the previous search.
4: Sometimes (about 1 in 10), the search fails with an ObjecNotFoundException.

Expected behavior:
As experienced, minus the exceptions.

My analysis:
Since the indexing is asynchronous, there will be a short period, where the search will include the deleted item.
If the entities where not cached, this should not be a problem, since they would simply not be included in the IN query.
In this case, however, all the entities are cached by EHCache in read-write mode.
I have identified the problem to be in SecondLevelCacheObjectsInitializer:

65: final boolean isIn2LCache = session.getSessionFactory().getCache().containsEntity( entityInfo.getClazz(), entityInfo.getId() );
66: if ( isIn2LCache ) {
67:     //load the object from the second level cache
68:     session.get( entityInfo.getClazz(), entityInfo.getId() );
69: }

Line 68 is where the exception occurs.
It appears that cache.containsEntity() is not a guarantee that the entity can actually be loaded.
In fact, in EHCache a lock object is placed in the cache when the item is deleted, and never removed again.
Thus the cache contains "something", just not a loadable entity.

My suggestion:
Wrap session.get() with a try-catch block, and ignore ObjectNotFoundException's (and probably EntityNotFoundException too, for JPA).

My workaround:
Manually evicting the entity from the 2nd level cache when deleting it.

Stacktrace:
org.hibernate.ObjectNotFoundException: No row with the given identifier exists: [com.jysk.resmgr.model.Resource#5663]
        at org.hibernate.impl.SessionFactoryImpl$2.handleEntityNotFound(SessionFactoryImpl.java:435)
        at org.hibernate.event.def.DefaultLoadEventListener.returnNarrowedProxy(DefaultLoadEventListener.java:320)
        at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:277)
        at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:152)
        at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:1090)
        at org.hibernate.impl.SessionImpl.get(SessionImpl.java:1005)
        at org.hibernate.impl.SessionImpl.get(SessionImpl.java:998)
        at org.hibernate.search.query.hibernate.impl.SecondLevelCacheObjectsInitializer.initializeObjects(SecondLevelCacheObjectsInitializer.java:68)
        at org.hibernate.search.query.hibernate.impl.PersistenceContextObjectsInitializer.initializeObjects(PersistenceContextObjectsInitializer.java:81)
        at org.hibernate.search.query.hibernate.impl.MultiClassesQueryLoader.executeLoad(MultiClassesQueryLoader.java:135)
        at org.hibernate.search.query.hibernate.impl.AbstractLoader.load(AbstractLoader.java:72)
        at org.hibernate.search.query.hibernate.impl.FullTextQueryImpl.list(FullTextQueryImpl.java:208)

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