Question

Background:

My team is dedicated to ensuring that straight from checkout, our code compiles and unit tests run successfully. To facilitate this and test some of our NHibernate mappings, we’ve added a SQLite DB to our repository which is a mirror of our production SQL Server 2005 database. We’re using the latest versions of: MbUnit3 (part of Gallio), System.Data.SQLite and NHibernate.

Problem:

I’ve discovered that the following unit test does not work with SQLite, despite executing without trouble against SQL Server 2005.

    [Test]     [Rollback]     public void CompleteCanPersistNode()     {         // returns a Configuration for either SQLite or SQL Server 2005 depending on how the project is configured.         Configuration config = GetDbConfig();           ISessionFactory sessionFactory = config.BuildSessionFactory();         ISession session = sessionFactory.OpenSession();          Node node = new Node();         node.Name = 'Test Node';         node.PhysicalNodeType = session.Get<NodeType>(1);          // SQLite fails with the exception below after the next line called.         node.NodeLocation = session.Get<NodeLocation>(2);          session.Save(node);         session.Flush();          Assert.AreNotEqual(-1, node.NodeID);         Assert.IsNotNull(session.Get<Node>(node.NodeID));     } 

The exception I’m getting (ONLY when working with SQLite) follows:

 NHibernate.ADOException: cannot open connection ---> System.Data.SQLite.SQLiteException:   The database file is locked database is locked     at System.Data.SQLite.SQLite3.Step(SQLiteStatement stmt)     at System.Data.SQLite.SQLiteDataReader.NextResult()     at System.Data.SQLite.SQLiteDataReader..ctor(SQLiteCommand cmd, CommandBehavior behave)     at System.Data.SQLite.SQLiteCommand.ExecuteReader(CommandBehavior behavior)     at System.Data.SQLite.SQLiteCommand.ExecuteNonQuery()     at System.Data.SQLite.SQLiteTransaction..ctor(SQLiteConnection connection, Boolean deferredLock)     at System.Data.SQLite.SQLiteConnection.BeginDbTransaction(IsolationLevel isolationLevel)     at System.Data.SQLite.SQLiteConnection.BeginTransaction()     at System.Data.SQLite.SQLiteEnlistment..ctor(SQLiteConnection cnn, Transaction scope)     at System.Data.SQLite.SQLiteConnection.EnlistTransaction(Transaction transaction)     at System.Data.SQLite.SQLiteConnection.Open()     at NHibernate.Connection.DriverConnectionProvider.GetConnection()     at NHibernate.Impl.SessionFactoryImpl.OpenConnection()     --- End of inner exception stack trace ---     at NHibernate.Impl.SessionFactoryImpl.OpenConnection()     at NHibernate.AdoNet.ConnectionManager.GetConnection()     at NHibernate.AdoNet.AbstractBatcher.Prepare(IDbCommand cmd)     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.LoadEntity(ISessionImplementor session, Object id, IType identifierType, Object optionalObject, String optionalEntityName, Object optionalIdentifier, IEntityPersister persister)     at NHibernate.Loader.Entity.AbstractEntityLoader.Load(ISessionImplementor session, Object id, Object optionalObject, Object optionalId)     at NHibernate.Loader.Entity.AbstractEntityLoader.Load(Object id, Object optionalObject, ISessionImplementor session)     at NHibernate.Persister.Entity.AbstractEntityPersister.Load(Object id, Object optionalObject, LockMode lockMode, ISessionImplementor session)     at NHibernate.Event.Default.DefaultLoadEventListener.LoadFromDatasource(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, 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.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.Get(String entityName, Object id)     at NHibernate.Impl.SessionImpl.Get(Type entityClass, Object id)     at NHibernate.Impl.SessionImpl.Get[T](Object id) D:\dev\598\Code\test\unit\DataAccess.Test\NHibernatePersistenceTests.cs 

When SQLite is used and the [Rollback] attribute is NOT specified, the test also completes successfully.

Question:

Is this an issue with System.Data.SQLite’s implementation of TransactionScope which MbUnit3 uses for [Rollback] or a limitation of the SQLite engine?

Is there some way to write this unit test, working against SQLite, that will rollback so as to avoid affecting the database each time the test is run?

Answer 1

Check if you’re not missing connection.release_mode=on_close in your SQLite NHibernate configuration. (reference docs)

BTW: always dispose your ISession and ISessionFactory.