MySQL ExecuteNonQuery hanging in mono

Question

I am in the process of moving from Visual Studio to Mono. I have a query which dumps about 190000 rows of a select statement into a a text file which I process from c#. Normally the whole thing goes well and is done in less than 7 seconds.

On mono however, it gets to the ExecuteNonQuery, and the OUTFILE is created successfully of exactly the same size as on the windows machine, but it never hits the breakpoint I've put just 1 line after the query.

In the application output you see:
Thread 2 started
Thread 2 exited
Thread 3 started
Thread 3 exited
....
Thread 60 started
...

you get the idea. Never seems to come back even though the query has done what it was supposed to do. I read a bug fix where nonquery hung for one user but not another so I tried a new user but no dice.

Any ideas?

MySqlConnection conn = new MySqlConnection(connectionString);
            MySqlCommand cmd = new MySqlCommand();

            cmd.Connection = conn;
            cmd.CommandText = "ThesDump";
            cmd.CommandType = System.Data.CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@filename", newThesFile);
            cmd.Parameters["@filename"].Direction = System.Data.ParameterDirection.Input;
            cmd.Parameters.Add("@lastupdate", MySqlDbType.DateTime);
            cmd.Parameters["@lastupdate"].Direction = System.Data.ParameterDirection.Output;

            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();