Question

i use C# threading and parsing some data and when i try to save and commit this data with fluent nhibernate i get deadlock. Isn’t commit thread safe by default? How to prevent deadlock here?

//problem and where i get deadlock
advertismentsDao.Save(ad);
advertismentsDao.CommitChanges();

public T Save(T entity)
{
    NHibernateSession.Save(entity);
    return entity;
}

public void CommitChanges()
{
    if (NHibernateSessionManager.Instance.HasOpenTransactionOn(SessionFactoryConfigPath))
    {
        NHibernateSessionManager.Instance.CommitTransactionOn(SessionFactoryConfigPath);
    }
    else
    {
        // If there's no transaction, just flush the changesslate
        NHibernateSessionManager.Instance.GetSessionFrom(SessionFactoryConfigPath).Flush();
    }
}

and error:

Transaction (Process ID 78) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
StackTrace:    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()
   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
   at System.Data.SqlClient.SqlDataReader.ConsumeMetaData()
   at System.Data.SqlClient.SqlDataReader.get_MetaData()
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader()
   at NHibernate.AdoNet.AbstractBatcher.ExecuteReader(IDbCommand cmd)
   at NHibernate.Id.IdentityGenerator.InsertSelectDelegate.ExecuteAndExtract(IDbCommand insert, ISessionImplementor session)
   at NHibernate.Id.Insert.AbstractReturningDelegate.PerformInsert(SqlCommandInfo insertSQL, ISessionImplementor session, IBinder binder)

Answer 1

This is SQL deadlock, not multithreading