const string clientAccount = "3801000BL040264";

            bool firstRun = true;
            var minMax = OracleInternetBank.OracleDb.Instance.GetMinMax(clientAccount);
            var rawList = OracleInternetBank.OracleDb.Instance.ListBolcardInvoiceLinq(clientAccount);

            for (int j = 0; j < 5; j++)
            {
                var startDate = DateTime.Now.AddYears((-3 - j));
                var endDate = DateTime.Now;

                GetForeachResult(clientAccount, rawList, minMax);

                if (firstRun)
                {
                    for (int i = 0; i < 5; i++)
                    {
                        GetForeachResult(clientAccount, rawList, minMax);
                    }

                    Console.WriteLine("Warm up finish");
                }
                var timerStart = DateTime.Now;

                for (int i = 0; i < 100; i++)
                {
                    GetForeachResult(clientAccount, rawList, minMax);
                }

                Console.WriteLine(String.Format("Foreach: {0}", (DateTime.Now - timerStart).Milliseconds));

                if (firstRun)
                {
                    for (int i = 0; i < 5; i++)
                    {
                        GetLinqResult(clientAccount, rawList, minMax);
                    }

                    Console.WriteLine("Warm up finish");
                }
                timerStart = DateTime.Now;

                for (int i = 0; i < 100; i++)
                {
                    GetLinqResult(clientAccount, rawList, minMax);
                }

                Console.WriteLine(String.Format("LINQ: {0}", (DateTime.Now - timerStart).Milliseconds));
                firstRun = false;
            }


            Console.WriteLine("Finished.");
            Console.ReadKey();



private static void GetLinqResult(string clientAccount, IEnumerable<InvoiceInfo> rawList, InvoiceMinMax minMax)
        {
            var rawUnpeedList = rawList.Where(info => info.Flag == 0);
            var rawPaedList = rawList.Where(info => info.Flag > 0);

            var digestList = new List<InvoicePeriod>();
            var curDate = minMax.Min;
            do
            {
                var list = rawUnpeedList.Where(info => info.Invoice == curDate);
                var total = 0f;

                var invoiceInfos = list as IList<InvoiceInfo> ?? list.ToList();
                if (invoiceInfos.Count > 0)
                {
                    digestList.Add(new InvoicePeriod(invoiceInfos.OrderBy(info => info.TranshDate).ToList(), curDate, total));
                }
                curDate = curDate.AddMonths(1);
            } while (curDate <= minMax.Max);


            var payeedList = new List<InvoicePeriod>();
            curDate = minMax.Min;
            do
            {
                var list = rawPaedList.Where(info => info.Invoice == curDate);
                var total = 0f;

                var invoiceInfos = list as IList<InvoiceInfo> ?? list.ToList();
                if (invoiceInfos.Count > 0)
                {
                    payeedList.Add(new InvoicePeriod(invoiceInfos.OrderBy(info => info.TranshDate).ToList(), curDate, total));
                }
                curDate = curDate.AddMonths(1);
            } while (curDate <= minMax.Max);
        }

        private static void GetForeachResult(string clientAccount, IEnumerable<InvoiceInfo> rawList, InvoiceMinMax minMax)
        {
            var rawUnpayedList = new List<InvoiceInfo>();
            var rawPayedList = new List<InvoiceInfo>();

            foreach (var row in rawList)
            {
                if (row.Flag == 0)
                {
                    rawUnpayedList.Add(row);
                }
            }
            foreach (var row in rawList)
            {
                if (row.Flag > 0)
                {
                    rawPayedList.Add(row);
                }
            }

            var unpayedList = new List<InvoicePeriod>();
            var curDate = minMax.Min;
            do
            {
                var list = new List<InvoiceInfo>();

                foreach (var row in rawUnpayedList)
                {
                    if (row.Invoice == curDate)
                    {
                        list.Add(row);
                    }
                }
                var total = 0f;
                if (list.Count > 0)
                {
                    list.Sort((p1, p2) => p1.TranshDate.CompareTo(p2.TranshDate)
                        );
                    unpayedList.Add(new InvoicePeriod(list, curDate, total));
                }
                curDate = curDate.AddMonths(1);
            } while (curDate <= minMax.Max);


            var payeedList = new List<InvoicePeriod>();
            curDate = minMax.Min;
            do
            {
                var list = new List<InvoiceInfo>();

                foreach (var row in rawPayedList)
                {
                    if (row.Invoice == curDate)
                    {
                        list.Add(row);
                    }
                }
                var total = 0f;
                if (list.Count > 0)
                {
                    list.Sort((p1, p2) => p1.TranshDate.CompareTo(p2.TranshDate)
                        );
                    payeedList.Add(new InvoicePeriod(list, curDate, total));
                }
                curDate = curDate.AddMonths(1);
            } while (curDate <= minMax.Max);
        }