AccessViolationException under heavy load

michal · **Posted:** Tue Jan 27, 2009 8:21 am

Welcome

I am experiencing very serious problems with NH-based ASP.NET appliaction under IIS7 (Windows Svr. 2008 64bit) . Several times a day I've got AccessViolationException on any NH operation , until I recycle the IIS worker process. Actually it stops application from working for customers. I am doing big research on this subject for week and still found nothing that helps (tried disabling DEP, splitting worker process etc. - nothing really helped)

Exception it is hard to repeat, only thing I have noticed it is more frequent under heavy load, when memory allocated for w3wp process is about 5GB or higher. I know that there should be no limit for process size in the 64-bit architecture (OK 8TB afaik) . And another thing - it happens at three different servers (two with 8GB and one with 16GB total RAM), so memory corruption is not the point. Please help, the thing is killing my reputation rapidly :(

Below is an example stacktrace, you can find AccessViolationException below, (as inner exception):

Code:

[HibernateException]
Creating a proxy instance failed
   at NHibernate.Proxy.Poco.Castle.CastleProxyFactory.GetProxy(Object id, ISessionImplementor session)
   at NHibernate.Tuple.Entity.AbstractEntityTuplizer.CreateProxy(Object id, ISessionImplementor session)
   at NHibernate.Persister.Entity.AbstractEntityPersister.CreateProxy(Object id, ISessionImplementor session)
   at NHibernate.Event.Default.DefaultLoadEventListener.CreateProxyIfNecessary(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options, IPersistenceContext persistenceContext)
   at NHibernate.Event.Default.DefaultLoadEventListener.ProxyOrLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
   at NHibernate.Event.Default.DefaultLoadEventListener.OnLoad(LoadEvent event, LoadType loadType)
   at NHibernate.Impl.SessionImpl.FireLoad(LoadEvent event, LoadType loadType)
   at NHibernate.Impl.SessionImpl.InternalLoad(String entityName, Object id, Boolean eager, Boolean isNullable)
   at NHibernate.Type.EntityType.ResolveIdentifier(Object id, ISessionImplementor session)
   at NHibernate.Type.EntityType.ResolveIdentifier(Object value, ISessionImplementor session, Object owner)
   at NHibernate.Engine.TwoPhaseLoad.InitializeEntity(Object entity, Boolean readOnly, ISessionImplementor session, PreLoadEvent preLoadEvent, PostLoadEvent postLoadEvent)
   at NHibernate.Loader.Loader.InitializeEntitiesAndCollections(IList hydratedObjects, Object resultSetId, ISessionImplementor session, Boolean readOnly)
   at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters)
   at NHibernate.Loader.Loader.ListUsingQueryCache(ISessionImplementor session, QueryParameters queryParameters, ISet`1 querySpaces, IType[] resultTypes)
   at NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet`1 querySpaces, IType[] resultTypes)
   at NHibernate.Hql.Classic.QueryTranslator.List(ISessionImplementor session, QueryParameters queryParameters)
   at NHibernate.Engine.Query.HQLQueryPlan.PerformList(QueryParameters queryParameters, ISessionImplementor session, IList results)
   at NHibernate.Impl.SessionImpl.List(String query, QueryParameters queryParameters, IList results)
   at NHibernate.Impl.SessionImpl.List(String query, QueryParameters parameters)
   at NHibernate.Impl.QueryImpl.List()
   at interfejsLib.Opcje.WczytajOpcje(Int32 IdModul, String Nazwa, Boolean CzyBezUkrytych)
   at interfejsLib.Opcje.FillCache(Hashtable _c)
   at interfejsLib.Opcje.get_OpcjeCache()
   at interfejsLib.Opcje.get_OpcjaCache(String nazwa)
   at interfejsLib.Opcje.get_mOpcjaString(String nazwa)
   at interfejsLib.Opcje.OpcjaString(String nazwa)
   at interfejs.index.Page_Load(Object sender, EventArgs e)
   at System.Web.UI.Control.OnLoad(EventArgs e)
   at System.Web.UI.Control.LoadRecursive()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
- - -

INNER [AccessViolationException] Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

   at System.Reflection.Emit.TypeBuilder._TermCreateClass(Int32 handle, Module module)
   at System.Reflection.Emit.TypeBuilder.CreateTypeNoLock()
   at System.Reflection.Emit.TypeBuilder.CreateType()
   at Castle.DynamicProxy.Generators.Emitters.AbstractTypeEmitter.BuildType()
   at Castle.DynamicProxy.Generators.ClassProxyGenerator.GenerateCode(Type[] interfaces, ProxyGenerationOptions options)
   at Castle.DynamicProxy.ProxyGenerator.CreateClassProxy(Type targetType, Type[] interfaces, ProxyGenerationOptions options, Object[] constructorArgs, IInterceptor[] interceptors)
   at Castle.DynamicProxy.ProxyGenerator.CreateClassProxy(Type targetType, Type[] interfaces, IInterceptor[] interceptors)
   at NHibernate.Proxy.Poco.Castle.CastleProxyFactory.GetProxy(Object id, ISessionImplementor session)

michal · **Posted:** Mon Mar 02, 2009 4:26 am

At least I've found a solution (or rather workaround, but actually it's better than "solution"), using NH proxy generators from http://nhforge.org eliminates calls to GenerateCode and TermCreateClass where the exception occurs. And it gives great performance boost too.

That's a pity that nobody here known that, it would save me big headaches. Maybe my answer will be helpfull for someone.