Получение заказов в ресторане из SQL Server

public (List<Order>, Dictionary<int, string>, Dictionary<int, string>) GetOrders(int RestaurantID, int StartID)
    {
        List<Order> Orders = null;
        Dictionary<int, string> MenuItemsXml = null;
        Dictionary<int, string> OrderHistoryXml = null;
        string sql = "SELECT ev.ID, ev.RestaurantID, ev.UserID, ev.DateCreated, ev.Amount, ev.AmountDiscounted, ev.TableNumber, (SELECT '|', FoodOrderDetail.ItemID, FoodOrderDetail.ItemName, FoodOrderDetail.Quantity, FoodOrderDetail.[Price], FoodOrderDetail.[Note] FROM FoodOrderDetail INNER JOIN FoodOrders a ON FoodOrderDetail.OrderID = a.ID WHERE a.ID = ev.ID ORDER BY DateCreated DESC FOR XML PATH('')) [OrderItems],(SELECT '|', FoodOrderHistory.[Status], FoodOrderHistory.[StatusDate] FROM FoodOrderHistory INNER JOIN FoodOrders a ON FoodOrderHistory.OrderID = a.ID WHERE a.ID = ev.ID ORDER BY StatusDate ASC FOR XML PATH('')) [OrderHistory] FROM FoodOrders ev WHERE ev.RestaurantID = @param1 AND ev.ID > @param2 AND ev.PreAuthorised = 1 ORDER BY ev.ID DESC;";

        using (var connection = new SqlConnection(ConnectionString))
        {
            using (SqlCommand command = new SqlCommand(sql, connection))
            {
                command.Parameters.Add(new SqlParameter("@param1", RestaurantID));
                command.Parameters.Add(new SqlParameter("@param2", StartID));
                connection.Open();
                using SqlDataReader dataReader = command.ExecuteReader(CommandBehavior.CloseConnection);
                if (dataReader.HasRows)
                {
                    Orders = new List<Order> { };
                    while (dataReader.Read())
                    {
                        Order objOrder = new Order();
                        objOrder.ID = Convert.ToInt32(dataReader["ID"]);
                        objOrder.UserID = Convert.ToInt32(dataReader["UserID"]);
                        objOrder.DateCreated = Convert.ToDateTime(dataReader["DateCreated"]);
                        objOrder.Amount = Convert.ToDecimal(dataReader["Amount"]);

                        if (dataReader["AmountDiscounted"] != DBNull.Value)
                        {
                            objOrder.Amount = Convert.ToDecimal(dataReader["AmountDiscounted"]);
                        }
                        if (dataReader["TableNumber"] != DBNull.Value)
                        {
                            objOrder.TableNumber = Convert.ToString(dataReader["TableNumber"]);
                        }
                        if (dataReader["OrderItems"] != DBNull.Value)
                        {
                            if(MenuItemsXml == null)
                            {
                                MenuItemsXml = new Dictionary<int, string>();
                            }
                            MenuItemsXml.Add(objOrder.ID, Convert.ToString(dataReader["OrderItems"]));
                        }
                        if(dataReader["OrderHistory"] != DBNull.Value)
                        {
                            if(OrderHistoryXml == null)
                            {
                                OrderHistoryXml = new Dictionary<int, string>();
                            }
                            OrderHistoryXml.Add(objOrder.ID, Convert.ToString(dataReader["OrderHistory"]));
                        }
                        Orders.Add(objOrder);
                    }
                }
                dataReader.Close();
            }
            if (connection.State == ConnectionState.Open)
            {
                connection.Close();
            }
        }
        return (Orders, MenuItemsXml, OrderHistoryXml);
    }

Вышеупомянутая функция вызывается этой функцией:

public List<Order> GetOrders(int RestaurantID, int StartID)
    {
        List<Order> Orders = null;
        Dictionary<int, string> OrderItemsXml = null;
        Dictionary<int, string> OrderHistoryXml = null;
        OrderData objData = new OrderData();

        try
        {
            (Orders, OrderItemsXml, OrderHistoryXml) = objData.GetOrders(RestaurantID, StartID);
        }
        catch (Exception ex)
        {
            logger.Error(ex);
        }

        if(OrderItemsXml != null)
        {
            foreach (var order in Orders)
            {
                try
                {
                    // stripe makes us store everything in major currency unit e.g. £1 is 100, so divide by 100 for when we later need to display values
                    if(order.Amount > 0)
                    {
                        order.Amount /= 100;
                    }
                    if (OrderItemsXml.ContainsKey(order.ID))
                    {
                        order.OrderItems = ConvertXmlToItemsList(OrderItemsXml[order.ID].TrimStart("|".ToCharArray()));
                    }
                    else
                    {
                        logger.Warn(string.Format("Dictionary OrderItemsXml does not contain OrderId Key of {0} in OrderManager", order.ID.ToString()));
                    }
                    if (OrderHistoryXml.ContainsKey(order.ID))
                    {
                        order.OrderHistory = ConvertXmlOrderHistory(OrderHistoryXml[order.ID].TrimStart("|".ToCharArray()));
                    }
                    else
                    {
                        logger.Warn(string.Format("Dictionary OrderHistoryXml does not contain OrderId Key of {0} in OrderManager", order.ID.ToString()));
                    }
                }
                catch (Exception ex)
                {
                    logger.Error(ex);
                }
            }
        }
        else
        {
            logger.Warn(string.Format("No order items found for RestaurantID {0} and StartID {1} in method GetOrders() in OrderManager", RestaurantID, StartID));
        }
        return Orders;
    }

Функция GetOrders () всегда закрывает соединение с базой данных? Иногда я получаю ошибки тайм-аута, и наиболее вероятная причина — в пуле соединений не хватает соединений. Когда это происходит, загрузка ЦП достигает 100%. Это происходит примерно раз в день.