SQL Server works slow after enable XP_CMDShell even disable until restart service

2 days ago I created a function that needs INSERT and UPDATE, and I enabled XP_CMDShell and do it by running a script. Afterwards, SQL Server works very slow for SELECT commands. Even very simple SELECT statement that runs after INSERT via separated command. I tested this behaviour on other databases and it giae same result that SELECT runs after some minutes. Also, I tested it on 2 other hosts with SQL Server 2014 and the result was the same. Function that I created to get value of it within another select statement: ALTER FUNCTION [Prg].[intCheckDelayedProcessProgram] ( @SalesOrderProductID INT, @MainProductTreeID INT, @ProductTreeID INT, @ProcessId INT, @additionalDays INT = 2, @currentDateReverceString VARCHAR(10) = NULL ) RETURNS INT AS BEGIN --declare @SalesOrderProductID INT = 40957, -- @MainProductTreeID INT = 93758, -- @ProductTreeID INT = 93758, -- @ProcessId INT = 4472, -- @additionalDays INT = 2, -- @currentDateReverceString VARCHAR(10) = null -- '30/09/1398' DECLARE @ProduceDailyProgramProductTree_Id INT, @ProgramQuantity INT, @startDate JalaliDate, @CurrentDate JalaliDate, @lastDate JalaliDate, @additionalDate JalaliDate, @holiDaysCount INT; IF(@currentDateReverceString IS NULL OR @currentDateReverceString = '') SET @CurrentDate = dbo.GetCurrentJalaliDate(); ELSE SET @CurrentDate = Gnr.RevercePersianDate(@currentDateReverceString); IF (@additionalDays IS NULL) SET @additionalDays = 2; DECLARE @allDelayedItemsCount INT = 0; BEGIN DECLARE @sql NVARCHAR(4000), @cmd VARCHAR(4000); DECLARE cursor_pdppt CURSOR FOR SELECT pdppt.ID, pdppt.ProgramQuantity, pdppt.[Date] FROM Prg.ProduceDailyProgramProductTree pdppt WHERE pdppt.SalesOrderProductID = @SalesOrderProductID AND pdppt.MainProductTreeID = @MainProductTreeID AND pdppt.ProductTreeID = @ProductTreeID AND pdppt.Process = @ProcessId AND ISNULL(pdppt.IsDelayed, 0) = 0 OPEN cursor_pdppt; FETCH NEXT FROM cursor_pdppt INTO @ProduceDailyProgramProductTree_Id, @ProgramQuantity, @startDate; WHILE @@FETCH_STATUS = 0 BEGIN SET @lastDate = Gnr.RevercePersianDate([Prg].[intGetLastDateForDelayedProcessProgram](@startDate, @additionalDays, @CurrentDate, 1)); IF (@CurrentDate.GetDate() > @lastDate.GetDate()) BEGIN IF ((SELECT COUNT(*) FROM Prg.ProduceDailyOperation pdo WHERE pdo.ProduceDailyProgramProductTreeID = @ProduceDailyProgramProductTree_Id AND pdo.Process = @ProcessId AND pdo.[Date].GetDate() > @lastDate.GetDate()) = 0) BEGIN SET @allDelayedItemsCount = @allDelayedItemsCount + @ProgramQuantity; END ELSE BEGIN SET @allDelayedItemsCount = @allDelayedItemsCount + (@ProgramQuantity - (SELECT SUM(pdo.ProducedQuantity) FROM Prg.ProduceDailyOperation pdo WHERE pdo.ProduceDailyProgramProductTreeID = @ProduceDailyProgramProductTree_Id AND pdo.Process = @ProcessId AND pdo.[Date].GetDate() 0) BEGIN IF (EXISTS(SELECT 1 FROM Prg.ProduceDailyProgramProductTreeDelayed pdppt WHERE pdppt.SalesOrderProductID = @SalesOrderProductID AND pdppt.MainProductTreeID = @MainProductTreeID AND pdppt.ProductTreeID = @ProductTreeID AND pdppt.Process = @ProcessId)) BEGIN SELECT @allDelayedItemsCount = @allDelayedItemsCount + (SELECT pdpptd.DelayedQuantity FROM Prg.ProduceDailyProgramProductTreeDelayed pdpptd WHERE pdpptd.SalesOrderProductID = @SalesOrderProductID AND pdpptd.MainProductTreeID = @MainProductTreeID AND pdpptd.ProductTreeID = @ProductTreeID AND pdpptd.Process = @ProcessId AND ISNULL(pdpptd.Active, 0) = 1 AND ISNULL(pdpptd.IsDeleted, 0) = 0); SELECT @sql = 'UPDATE [Prg].[ProduceDailyProgramProductTreeDelayed] SET DelayedQuantity = ' + CONVERT(VARCHAR(10), @allDelayedItemsCount) + 'WHERE SalesOrderProductID = ' + CONVERT(VARCHAR(10), @SalesOrderProductID) + 'AND MainProductTreeID = ' + CONVERT(VARCHAR(10), @MainProductTreeID) + 'AND ProductTreeID = ' + CONVERT(VARCHAR(10), @ProductTreeID) + 'AND Process = ' + CONVERT(VARCHAR(10), @ProcessId) +';'; END ELSE BEGIN SELECT @sql = 'INSERT INTO [Prg].[ProduceDailyProgramProductTreeDelayed] (SalesOrderProductID, MainProductTreeID, Process, ProductTreeID, DelayedQuantity, Active, IsDeleted) VALUES (' + CONVERT(VARCHAR(10), @SalesOrderProductID) + ', ' + CONVERT(VARCHAR(10), @MainProductTreeID) + ', ' + CONVERT(VARCHAR(10), @ProcessId) + ', ' + CONVERT(VARCHAR(10), @ProductTreeID) + ', ' + CONVERT(VARCHAR(10), @allDelayedItemsCount) + ', ''1'', ''0'')'; END; SELECT @cmd = 'sqlcmd -S ' + @@SERVERNAME + ' -d ' + DB_NAME() + ' -Q "' + @sql + '"' EXEC MASTER..XP_CMDSHELL @cmd , 'no_output' END ELSE IF(EXISTS(SELECT 1 FROM Prg.ProduceDailyProgramProductTreeDelayed pdpptd WHERE pdpptd.SalesOrderProductID = @SalesOrderProductID AND pdpptd.MainProductTreeID = @MainProductTreeID AND pdpptd.ProductTreeID = @ProductTreeID AND pdpptd.Process = @ProcessId AND ISNULL(pdpptd.Active, 0) = 1 AND ISNULL(pdpptd.IsDeleted, 0) = 0)) BEGIN SELECT @allDelayedItemsCount = (SELECT pdpptd.DelayedQuantity FROM Prg.ProduceDailyProgramProductTreeDelayed pdpptd WHERE pdpptd.SalesOrderProductID = @SalesOrderProductID AND pdpptd.MainProductTreeID = @MainProductTreeID AND pdpptd.ProductTreeID = @ProductTreeID AND pdpptd.Process = @ProcessId AND ISNULL(pdpptd.Active, 0) = 1 AND ISNULL(pdpptd.IsDeleted, 0) = 0); END; END; RETURN @allDelayedItemsCount; END JalaliDate is user defined type to hold persian date time by Assembly. Gnr.RevercePersianDate function to convert string persian date to JalaliDate. [Prg].[intGetLastDateForDelayedProcessProgram] other function to calculate specified date by Holidays that I think dose not issue. **UPDATE 1** I test function codes by pass parameter values by inline declare and set test values. Then, user Sql Server Profiler to check script of function, that see scripts stops on this line SET @CurrentDate = dbo.GetCurrentJalaliDate() that use function of Assembly. Execution running without any error and not responding!! Note: I test SELECT dbo.GetCurrentJalaliDate() that responding very fast without error! **UPDATE 2** I call function [Prg].[intCheckDelayedProcessProgram] within SP and inside a complex SELECT statement, that can't call SP in select, so just solution for me was define function. Code run in local server that is together with all data and other SP and functions. If there is alternative for CURSOR help me to rewrite function with it.