NHibernate transaction problem with multiple sessions

Question

I have set up NHibernate to run in a windows service with MS Sql Server 2008. I use a regular TransactionScope to ensure that the operation is atomic. NHibernate is set up to create a session factory per assembly.

I want to write changes to objects from 3 different assemblies. Everything works fine when I work with one or two assemblies at the time, but when I add reading from a third assembly I run into problems.

I.e. Reading/Writing to and from objects in two assemblies works fine, adding objects from the assembly creates problems. However, reading from the third assembly without working with objects from the other two assemblies also works fine. I have a feeling that the sessions are creating problems for each other.

My code is like this:

using (var scope = new TransactionScope())
{
//Read object 1
//Do changes to object 2
//Do changes to object 3
scope.Complete();
}

When I try to complete my transaction scope (via scope.Complete()) I get the following error message:

System.Data.SqlClient.SqlException: Microsoft Distributed Transaction Coordinator (MS DTC) has stopped this transaction.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
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.SqlInternalConnectionTds.ExecuteTransaction(TransactionRequest transactionRequest, String name, IsolationLevel iso, SqlInternalTransaction internalTransaction, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlDelegatedTransaction.SinglePhaseCommit(SinglePhaseEnlistment enlistment) 
System.Transactions.TransactionAbortedException: The transaction has aborted.
at System.Transactions.TransactionStatePromotedAborted.PromotedTransactionOutcome(InternalTransaction tx)
at System.Transactions.TransactionStatePromotedEnded.EndCommit(InternalTransaction tx)
at System.Transactions.CommittableTransaction.Commit()
at System.Transactions.TransactionScope.InternalDispose()
at System.Transactions.TransactionScope.Dispose()

Any thoughts?

Why don't you use one session factory for the 3 assemblies? Any special need? — Pedro, Nov 02 '10 at 17:07

score 0 · Accepted Answer · answered Nov 03 '10 at 07:17

0

Firstly check that you are correctly using nHibernate and TransactionScope together. Here is how it should be done (taken from Avoiding Leaking Connections With NHibernate And TransactionScope):

        using (var scope = new TransactionScope(TransactionScopeOption.Required))
        {
            using (var session = sessionFactory.OpenSession())
            using (var transaction = session.BeginTransaction())
            {
                // do what you need to do with the session
                transaction.Commit();
            }
            scope.Complete();
        }

The error you are getting is common if are 'reusing' sessions across multiple transactions. I found it to be a world of pain, as distributed transactions are committed and rolled back on a background threads so you cannot know when you can reuse them. Also the nHibernate code is not thread safe. Hence I suggest never reuse sessions, always destroy them as per the code above.

answered Nov 03 '10 at 07:17

Iain

10,814
3
36
31

I thought in NHibernate 2.1 the TransactionScope was supported out of the box (http://stackoverflow.com/questions/646318/nhibernate-with-transactionscope). – Unyttig Nov 03 '10 at 08:16
It is supported under certain conditions. The above is the safest way of using it. I had a prod issue with rollbacks causing a connection leak. When I tried to fix it I ran into other issues, such as the one you are getting. In the end, the above worked. – Iain Nov 03 '10 at 08:38
Ok. Thanks for the replies! Do you know where I can find documentation about how NHibernate works together with TransactionScopes? I have tried NHForge and the book 'NHibernate in action' but both seem somewhat outdated. – Unyttig Nov 04 '10 at 08:47
Sorry I don't. I pieced it together from blogs, discussions, source code, and experience. – Iain Nov 04 '10 at 12:07

NHibernate transaction problem with multiple sessions

1 Answers1