我写的代码是保存用户从一个程序在sql表，但当15个用户在同一时间保存或更新我得到1分钟的延迟和程序没有响应。。。你能帮助我吗。这是我的密码。

public bool GetUser(ref clsConnection c)
    {
        try
        {
            MySqlConnection connect = new MySqlConnection(connectionMysql);
            connect.Open();
            MySqlCommand query = new MySqlCommand("SELECT * FROM Users WHERE User_Name='" + Escape(c.Username) + "'", connect);
            query.Prepare();
            MySqlDataReader dr = query.ExecuteReader();
            if (dr.Read())
            {
                c.Username = dr[1].ToString();
                c.NoColPlyName = dr[2].ToString();
                c.Cash = double.Parse(dr[3].ToString());
                c.Password = dr[4].ToString();
            }
            else
            {
                dr.Close();
                connect.Close();
                return false;
            }
            dr.Close();
            connect.Close();
            return true;
        }
    }
    public void UpdateUser(clsConnection u)
    {
        MySqlConnection cn = new MySqlConnection(connectionMysql);
        try
        {
            if (u.Username != "")
            {
                cn.Open();
                MySqlCommand query = new MySqlCommand(@"UPDATE Users SET User_Name=@User_Name,User_PlyName=@User_PlyName,User_Cash=@User_Cash,User_Passowrd=@User_Password WHERE User_Name='" + Escape(u.Username) + "';", cn);
                if (query != null)
                {
                    query.Parameters.AddWithValue("@User_Name", Escape(u.Username));
                    query.Parameters.AddWithValue("@User_PlyName", Escape(u.NoColPlyName));
                    query.Parameters.AddWithValue("@User_Cash", u.Cash);
                    query.Parameters.AddWithValue("@User_Passowrd", u.Password);
                    cn.Close();
                    return;
                }
                else
                {
                    return;
                }
            }
        }
    }
    public void AddUser(clsConnection c)
    {
        try
        {
            if (c.Username != "")
            {
                Query(@"INSERT INTO Users (User_Name,User_PlayerName,User_Cash,User_Passowrd) VALUES ('" +
                    Escape(c.Username) + "', '" +
                    Escape(c.NoColPlyName) + "', '" +
                    c.Cash + "', '" +
                    Espace(c.Passoword) + "');");
            }
        }
    }

//当15个用户尝试连接到程序时，程序没有响应，延迟非常大。当<10个用户连接到程序时，程序运行良好，但+10延迟较大。。。