Comments on: SSIS – Avoiding the Sort Components

By: hello

hello — Fri, 08 Apr 2011 08:29:10 +0000

Its Really helpful.

By: Deepak T

Deepak T — Thu, 11 Nov 2010 03:51:01 +0000

This article was helpful, thanks..

By: Santhosh

Santhosh — Wed, 06 Oct 2010 05:46:35 +0000

Hi Phil/Guna,

Since i am very new to SSIS i need some clarifications.
Correct me if i am wrong as per the above discussion setting the IsSortProperty to true indicates Merge Join component that the data is Sorted form where as the data internally would not be sorted ???

I have used two OLE DB Source wher i have set the IsSorted Property to true and also i have set sort Key Position,the rows coming out of the Merge join here is 4 which is Incorrect.
But If use the Sort tranfomation after this OLE DB Source i am getting 13 rows which is the Proper result.

So can u please tell me the difference between the IsSortedProperty and the Sort Tranfomation.

Thank u in advance.

Santhosh Hiriyanna

By: Phil Brammer

Phil Brammer — Wed, 30 Sep 2009 03:07:50 +0000

Guna,
Yes, that’s correct. Only set the IsSorted property to true if your source is, well, sorted. Actually, to be more specific, use this property only if your SortKeyPosition columns are specified as the source is actually sorted. In other words if the source is sorted on the first column in the file, but you need to use the Merge Join component and joining on the second column in the source file, you should not use the IsSorted property, if the file is only sorted by the first column.

If your flat file or database source is not sorted, then setting IsSorted to True can have negative effects when trying to use components like the Merge or Merge Join.

By: Guna

Guna — Tue, 29 Sep 2009 22:35:06 +0000

Phil,
The IsSorted is available for flat files, but that is only useful if the data on the flat file is sorted, right?
what if the flat file data is not sorted? then we can’t specify on ORDER BY, and so we have to use the Sort component.
Correct me if I’m wrong?
thanks.

By: Phil Brammer

Phil Brammer — Tue, 29 Sep 2009 16:28:02 +0000

Ryan,
That is not true – you can still use the above techniques for flat files. The IsSorted property is available for flat files as well.

By: Ryan Shirley

Ryan Shirley — Mon, 28 Sep 2009 17:01:02 +0000

Thanks for the post, Phil. I agree that sorting on the database side is faster and always preferred. Unfortunately you still have to resort to the Sort component when using flat files as a data source. The one bonus is that the Sort component also lets you remove duplicate values in your sort key. So, if you are trying to do a ‘SELECT DISTINCT’ from a flat file, Sort is your friend.

By: James Rowland-Jones

James Rowland-Jones — Sun, 20 Sep 2009 09:55:48 +0000

Hi Phil,

Great post and a very important area to highlight. As I see it the big problem with the SORT component is that the bigger the sort the slower it gets – and the performance degradation isn’t linear it’s n log n. Invariably users don’t find this out till they hit the full production volume by which time the Solution has been built and tested. The existence of a SORT inside a dataflow is definitely a “smell” for me.

How I wish the SSIS team would buy NSORT for the product…

Cheers, James