SSIS Package Performance and Timeout Exception

Recently I deployed a package to production and started getting this error;

System.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired.  The timeout period elapsed prior to completion of the operation or the server is not responding. ---> System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out     at Microsoft.SqlServer.Dts.Pipeline.ScriptComponentHost.HandleUserException(Exception e)     at Microsoft.SqlServer.Dts.Pipeline.ScriptComponentHost.PostExecute()     at Microsoft.SqlServer.Dts.Pipeline.ManagedComponentHost.HostPostExecute(IDTSManagedComponentWrapper100 wrapper)  ClientConnectionId:b35cae06-1c27-4b61-9a32-6bf173753803  Error Number:-2,State:0,Class:11

After doing some research I found this;

SQL Server remote query timeout default value is 600seconds which is 10 minutes wait. The server that runs the package will wait for this amount of time before terminating remote sessions.

Lets increase this. I am setting this to 7200 seconds that’s 120 min that’s 2 hours. both on client and server.

Run this command on server;

EXEC sp_configure 'remote query timeout', 7200
RECONFIGURE

This might take some time. On my server it took 4 minutes.

Now run SSIS Package without re-deployment. Will it work? If no, then you need to set timeout in destination task;

For script component We can use something like this;

SqlCommand cmd = new SqlCommand(vSqlStatement, sqlConn);
/*
   7200 sec = 120 min = 2 hours. This can be set to 0 for non timeout at all
   Will this work? It also depends on server timeout settings. In most SQL install, SQL default timeout for remote queries is 600 seconds, 10 minutes.
*/
cmd.CommandTimeout = 7200;
sqlReader = cmd.ExecuteReader();

SSIS moves data using buffers. The default buffer size is 10 megabytes, with a maximum buffer size of 2^31-1 bytes. The default maximum number of rows is 10,000.

IF you look into destination buffer size, it is set to 0, which is default. If server does not support more horsepower then we can change this value to reduce buffer size, say change it from 0 to 500.

There is another good property that can help to adjust buffer size is AutoAdjustBufferSize.  Set AutoAdjustBufferSize property to true on DataFlow Task. This helps to improve performance.

Resources

Execution timeout expired the timeout period elapsed prior to completion

https://stackoverflow.com/questions/16651945/timeout-expired-the-timeout-period-elapsed-prior-to-completion-of-the-operation

https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/configure-the-remote-query-timeout-server-configuration-option?view=sql-server-ver15

https://www.mssqltips.com/sqlservertip/4221/improving-data-flow-performance-with-ssis-autoadjustbuffersize-property/

https://www.mssqltips.com/sqlservertip/3217/improve-ssis-data-flow-buffer-performance/

SQL Server IMAGE and VARBINARY Data Types

How to get SQL Data in chunks from remote server

OFFSET FETCH is a feature added to the ORDER BY clause beginning with the SQL Server 2012 edition. It can be used to extract a specific number of rows starting from a specific index.

Here is a simple example;

SELECT * FROM [dbo].[tblSample] 
order by SampleId 
OFFSET 0 ROWS
FETCH NEXT 10 ROWS ONLY

This instruct SQL Server to start from first record and return 10 records only.

Let’s write a dynamic sql to get data in batches; For example we have 7 records from database and we would like to get 3 records on each round trip;

DECLARE @RowCount INT, @RowIncrement INT, @RowsInChunk INT, @RemainingRows INT, @SourceQuery NVARCHAR(255)
DECLARE @RowIncrementValue INT, @BatchValue INT
DECLARE @SQL_Select NVARCHAR(4000);
DECLARE @RowIncrementCheck INT;

SET @RowCount = 7;
SET @RowIncrement = 0;
SET @RowsInChunk = 3;

--initial value
SET @RowIncrementValue = @RowIncrement
SET @BatchValue = @RowsInChunk

--loop through all records
WHILE (@RowIncrement <= @RowCount)
BEGIN

	--prepare SQL statement
	SET @SQL_Select =
	'SELECT *
	FROM [dbo].[tblSample] 
	order by SampleId 
	OFFSET  ' + CAST(@RowIncrementValue AS NVARCHAR) + ' ROWS ' + CHAR(13) +
	'FETCH NEXT ' + CAST(@BatchValue AS NVARCHAR) + ' ROWS ONLY'

	--EXECUTE sp_executesql @SQL_Select
	PRINT @SQL_SELECT

	SET @RowIncrement = @RowIncrement + @RowsInChunk
	SET @RowIncrementValue = @RowIncrement

	--calculate remaining rows
	SET @RemainingRows = @RowCount - @RowIncrement
	PRINT 'Remaining Rows ' +  CAST(@RemainingRows AS NVARCHAR)
	IF (@RemainingRows <= @RowsInChunk) AND (@RowIncrement <= @RowCount)
	BEGIN
		--short circuit this loop
		SET @BatchValue = @RemainingRows
		SET @RowIncrement = @RowCount
	END
END

Here is the result of 3 dynamic sql for 7 records;

SELECT *
	FROM [dbo].[tblSample] 
	order by SampleId 
	OFFSET  0 ROWS 
FETCH NEXT 3 ROWS ONLY
SELECT *
	FROM [dbo].[tblSample] 
	order by SampleId 
	OFFSET  3 ROWS 
FETCH NEXT 3 ROWS ONLY
SELECT *
	FROM [dbo].[tblSample] 
	order by SampleId 
	OFFSET  6 ROWS 
FETCH NEXT 1 ROWS ONLY

In the query above, OFFSET 0 is used to skip 0 rows and FETCH 3 ROWS ONLY is used to extract only 3 rows.

To get additional information about the ORDER BY clause and OFFSET FETCH feature, refer to the official documentation: Using OFFSET and FETCH to limit the rows returned.

Resources

Getting data from remote server

C# expression trees

We want to treat lambda expressions as expression trees and look inside them instead of executing them. For example, LINQ to SQL gets the expression and converts it to the equivalent SQL statement and submits it to server (rather than executing the lambda).

With Lambda expressions we can write less code, and the code will be more readable.

A lambda expression uses the lambda operator => which means goes to.

arguments => expession

The expression reads: arguments goes to expression.

Let’s start with a common example;

using System;

namespace Lambdas
{
    class Program
    {
        static void Main()
        {
            Console.WriteLine(Square(5));
            Console.ReadLine();
        }

        static int Square(int num)
        {
            return num * num;
        }
    }
}

we declare a method called Square of type int with one input parameter of type int. It multiplies the number and returns the result.

In the Main() method we call our Square method with an int as a parameter.

We can convert this function into a Lambda expression. This is what it would look like:

num => num * num;

This expression would read: num goes to calculation (num * num).

This expression is short and easily readable once we get used to it. The catch though, is that a Lambda expression must be assigned to a delegate.

Resources

https://stackoverflow.com/questions/793571/why-would-you-use-expressionfunct-rather-than-funct

https://tyrrrz.me/blog/expression-trees

https://thesharperdev.com/an-introduction-to-c-expression-trees/

Remove all spaces from strings using sql

I wanted to remove following spaces and special characters from these strings;

'a. Personnel '
'j.  Indirect Charges '

I tried to use following SQL to get rid of all spaces;

SELECT DISTINCT TRIM(LOWER(REPLACE(BudgetCategories, ' ', ''))) BudgetCategories
FROM [dbo].[MyTable]

Still the trailing spaces were there. I guess there is a special character involved, so i tried this one;

SELECT DISTINCT LTRIM(RTRIM(LOWER((REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(BudgetCategories, ' ', ''), CHAR(10), CHAR(32)),CHAR(13), CHAR(32)),CHAR(160), CHAR(32)),CHAR(9),CHAR(32))))))
FROM [dbo].[MyTable]

This did the trick and I was able to get this output;

'a.personnel'
'j.indirectcharges'

References

https://stackoverflow.com/questions/21585914/trim-spaces-in-string-ltrim-rtrim-not-working