Hi,
We're currently having an issue that seems to be caused because the
Transaction.TransactionCompleted event is fired on a different thread
when using TransactionScope.
When NHibernate handles this event it closes the database connection.
However by this time another transaction and database call has already
started on the main thread. NHibernate has opened the connection for
the second call and expects it to remain open.
Detailed information is below.
Any comments would be appreciated.
Thanks,
Norman
Timeline:
MAIN THREAD: SessionFactory.OpenSession() // without passing a
connection
MAIN THREAD: using (new TransactionScope())
MAIN THREAD: SomeDatabaseWork();
MAIN THREAD: // NHibernate opens connection
MAIN THREAD: // NHibernate does database work
MAIN THREAD: // NHibernate closes connection
MAIN THREAD: // SomeDatabaseWork(); returns
MAIN THREAD: TransactionScope.Complete();
MAIN THREAD: TransactionScope.Dispose(); // from using
MAIN THREAD: using (new TransactionScope())
MAIN THREAD: MoreDatabaseWork();
MAIN THREAD: // NHibernate opens connection
ANOTHER THREAD: Transaction.TrasactionCompleted event fires
ANOTHER THREAD: Nhibernate event handler closes connection
MAIN THREAD: // NHibernate does database work --> EXCEPTION
HERE
Exception:
NHibernate.ADOException was unhandled by user code
Message="could not execute query\r\n[ select * from blah]"
Source="NHibernate"
SqlString="select * from blah"
StackTrace:
at NHibernate.Loader.Loader.DoList(ISessionImplementor session,
QueryParameters queryParameters)
at
NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor
session, QueryParameters queryParameters)
at NHibernate.Loader.Loader.List(ISessionImplementor session,
QueryParameters queryParameters, ISet`1 querySpaces, IType[]
resultTypes)
at
NHibernate.Loader.Criteria.CriteriaLoader.List(ISessionImplementor
session)
at NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria,
IList results)
at NHibernate.Impl.CriteriaImpl.List(IList results)
at NHibernate.Impl.CriteriaImpl.List[T]()
at
NHibernate.Linq.Visitors.ImmediateResultsVisitor`1.GetElementList(MethodCallExpression
call, Int32 count)
at
NHibernate.Linq.Visitors.ImmediateResultsVisitor`1.HandleFirstOrDefaultCall(MethodCallExpression
call)
at
NHibernate.Linq.Visitors.ImmediateResultsVisitor`1.VisitMethodCall(MethodCallExpression
call)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression
exp)
at
NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression
exp)
at
NHibernate.Linq.Visitors.ImmediateResultsVisitor`1.GetResults(MethodCallExpression
expr)
at
NHibernate.Linq.Visitors.RootVisitor.HandleImmediateResultsCall(MethodCallExpression
call)
at
NHibernate.Linq.Visitors.RootVisitor.VisitMethodCall(MethodCallExpression
expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression
exp)
at
NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression
exp)
at
NHibernate.Linq.Visitors.NHibernateQueryTranslator.TranslateInternal(Expression
expression)
at
NHibernate.Linq.Visitors.NHibernateQueryTranslator.Translate(Expression
expression, QueryOptions queryOptions)
at
NHibernate.Linq.NHibernateQueryProvider.TranslateExpression(Expression
expression)
at NHibernate.Linq.NHibernateQueryProvider.Execute(Expression
expression)
at
NHibernate.Linq.QueryProvider.System.Linq.IQueryProvider.Execute[T]
(Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1
source)
at our code
at SyncInvokeGetGroupWellStates(Object , Object[] , Object[] )
at
System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object
instance, Object[] inputs, Object[]& outputs)
at
System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc&
rpc)
InnerException: System.InvalidOperationException
Message="Invalid operation. The connection is closed."
Source="System.Data.OracleClient"
StackTrace:
at
System.Data.OracleClient.OracleConnection.GetOpenInternalConnection()
at
System.Data.OracleClient.OracleConnection.get_ErrorHandle()
at
System.Data.OracleClient.OracleDataReader.FillColumnInfo()
at
System.Data.OracleClient.OracleDataReader..ctor(OracleCommand command,
OciStatementHandle statementHandle, String statementText,
CommandBehavior commandBehavior)
at
System.Data.OracleClient.OracleCommand.ExecuteReader(CommandBehavior
behavior)
at
System.Data.OracleClient.OracleCommand.ExecuteDbDataReader(CommandBehavior
behavior)
at
System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader()
at
NHibernate.AdoNet.AbstractBatcher.ExecuteReader(IDbCommand cmd)
at NHibernate.Loader.Loader.GetResultSet(IDbCommand st,
Boolean autoDiscoverTypes, Boolean callable, RowSelection selection,
ISessionImplementor session)
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)
InnerException:
Possible Workarounds:
1. Provide NHibernate with a connection when opening a session; or
2. Create a TransactionScope for duration of session (not ideal)
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