Using MySQLConnection in C# does not close properly

Question

Final solution:

The connection was added to the connection pool. So I closed it, but it still remained physically open. With the ConnectionString Parameter \"Pooli

Answer 1

According to the mysql docs, the MySQLConnection is not closed when it goes out of scope. Therefore you must not use it inside a using.

Quote... "If the MySqlConnection goes out of scope, it is not closed. Therefore, you must explicitly close the connection by calling MySqlConnection.Close or MySqlConnection.Dispose."

Answer 2

You need to wrap the Command and the DataReader in using statements as well.

Answer 3

Im unsure about mysqlconnection but the sql server counter part uses Connection pooling and does not close when you call close instead it puts it in the connection pool!

Edit: Make sure you dispose the Reader, Command, and Connection object!

Edit: Solved with the ConnectionString Parameter "Pooling=false" or the static methods MySqlConnection.ClearPool(connection) and MySqlConnection.ClearAllPools()

Answer 4

Have a look at using something like this:

private static IEnumerable<IDataRecord> SqlRetrieve(
    string ConnectionString, 
    string StoredProcName,
    Action<SqlCommand> AddParameters)
{
    using (var cn = new SqlConnection(ConnectionString))
    using (var cmd = new SqlCommand(StoredProcName, cn))
    {
        cn.Open();
        cmd.CommandType = CommandType.StoredProcedure;

        if (AddParameters != null)
        {
            AddParameters(cmd);
        }

        using (var rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
        {
            while (rdr.Read())
                yield return rdr;
        }
    }
}