Hello there,
We are having intermittent problems with a windows service running over WCF (single instance) with NHibernate.
We are getting occasional errors that are causing our service to fail:
11:35:27.023 [26] ERROR NHibernate.Event.Default.AbstractFlushingEventListener - Could not synchronize database state with session
NHibernate.StaleStateException: Unexpected row count: 0; expected: 1
at NHibernate.AdoNet.Expectations.BasicExpectation.VerifyOutcomeNonBatched(Int32 rowCount, IDbCommand statement)
at NHibernate.AdoNet.NonBatchingBatcher.AddToBatch(IExpectation expectation)
at NHibernate.Persister.Entity.AbstractEntityPersister.Delete(Object id, Object version, Int32 j, Object obj, SqlCommandInfo sql, ISessionImplementor session, Object[] loadedState)
at NHibernate.Persister.Entity.AbstractEntityPersister.Delete(Object id, Object version, Object obj, ISessionImplementor session)
at NHibernate.Action.EntityDeleteAction.Execute()
at NHibernate.Engine.ActionQueue.Execute(IExecutable executable)
at NHibernate.Engine.ActionQueue.ExecuteActions(IList list)
at NHibernate.Event.Default.AbstractFlushingEventListener.PerformExecutions(IEventSource session)
12:44:13.357 [38] ERROR NHibernate.Transaction.AdoTransaction - Commit failed
System.Data.SqlClient.SqlException: The COMMIT TRANSACTION request has no corresponding BEGIN TRANSACTION.
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.TdsExecuteTransactionManagerRequest(Byte[] buffer, TransactionManagerRequestType request, String transactionName, TransactionManagerIsolationLevel isoLevel, Int32 timeout, SqlInternalTransaction transaction, TdsParserStateObject stateObj, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlInternalConnectionTds.ExecuteTransactionYukon(TransactionRequest transactionRequest, String transactionName, IsolationLevel iso, SqlInternalTransaction internalTransaction, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlInternalTransaction.Commit()
at System.Data.SqlClient.SqlTransaction.Commit()
at NHibernate.Transaction.AdoTransaction.Commit()
and
NHibernate.HibernateException: disconnected session
at NHibernate.Collection.AbstractPersistentCollection.ForceInitialization()
at NHibernate.Engine.StatefulPersistenceContext.InitializeNonLazyCollections()
at NHibernate.Event.Default.DefaultLoadEventListener.AssembleCacheEntry(CacheEntry entry, Object id, IEntityPersister persister, LoadEvent event)
at NHibernate.Event.Default.DefaultLoadEventListener.LoadFromSecondLevelCache(LoadEvent event, IEntityPersister persister, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.DoLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.Load(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.TypeFactory.Assemble(Object[] row, ICacheAssembler[] types, ISessionImplementor session, Object owner)
at NHibernate.Cache.Entry.CacheEntry.Assemble(Object[] values, Object result, Object id, IEntityPersister persister, IInterceptor interceptor, ISessionImplementor session)
at NHibernate.Event.Default.DefaultLoadEventListener.AssembleCacheEntry(CacheEntry entry, Object id, IEntityPersister persister, LoadEvent event)
at NHibernate.Event.Default.DefaultLoadEventListener.LoadFromSecondLevelCache(LoadEvent event, IEntityPersister persister, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.DoLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.Load(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.Get(Type clazz, Object id, LockMode lockMode)
at X.X.DomainData.Implementation.CoreDao.GetEntity[T](Object id)
at X.X.DomainData.Implementation.UserDao.GetThing(Int32 engineerId)
at X.X.CaseManagement.Implementation.Managers.UserManager.GetThing(Int32 engineerID)
Here is our session manager:
Code:
using System;
using NHibernate;
using NHibernate.Cfg;
namespace X.X.DomainData.Implementation
{
public sealed class SessionManager
{
[ThreadStatic] private static ISession _session;
private readonly Configuration _configuration;
private readonly ISessionFactory _sessionFactory;
#region Constructor
#region Singleton
public static SessionManager Instance
{
get { return Singleton.Instance; }
}
private class Singleton
{
internal static readonly SessionManager Instance = new SessionManager();
}
#endregion
private SessionManager()
{
_configuration = new Configuration();
Configuration.Configure();
Configuration.AddAssembly(GetType().Assembly);
Configuration.Properties.Add("prevalenceBase", "cmm-cache");
//get the session factory
_sessionFactory = Configuration.BuildSessionFactory();
}
#endregion
#region NHibernate Setup
public Configuration Configuration
{
get { return _configuration; }
}
internal ISessionFactory SessionFactory
{
get { return _sessionFactory; }
}
public void Close()
{
SessionFactory.Close();
}
#endregion
#region NHibernate Sessions
public ISession Session
{
get
{
ISession session = _session;
//if it's an open session, that's all
if (session != null && session.IsOpen)
return session;
//if not open, open a new session
return OpenSession();
}
}
public ISession OpenSession()
{
ISession session = SessionFactory.OpenSession();
_session = session;
return session;
}
#endregion
}
}
We are using this property:
<property name="current_session_context_class">thread_static</property>
Can anybody explain what causes this error, why it causes the service to freeze and how we can get around it?
Many thanks in anticipation,
Carl
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