AsParallel() in join LINQ statement

A question rose after the parallel programming session delivered during the Application Life Cycle User Conference 2010 at Kuala Lumpur Convention Center (KLCC) back in July 2010.

The question is how many AsParallel method should we use in a LINQ statement with join keyword. Let’s use examples to proof this.

We have the first LINQ join statement.

       var custSupJoin =

          from sup in suppliers

          join cust in customers on sup.Country equals cust.Country

          select new { Country = sup.Country, SupplierName = sup.SupplierName, CustomerName =   cust.CompanyName };

 

The second statement has one AsParallel method.

      var custSupJoin =

          from sup in suppliers

          join cust in customers.AsParallel() on sup.Country equals cust.Country

          select new { Country = sup.Country, SupplierName = sup.SupplierName, CustomerName = cust.CompanyName };

 

The last statement has two AsParallel methods.

 

       var custSupJoin =

          from sup in suppliers.AsParallel()

          join cust in customers.AsParallel() on sup.Country equals cust.Country

          select new { Country = sup.Country, SupplierName = sup.SupplierName, CustomerName = cust.CompanyName };

 

We run this 3 statement in Lenovo T400. The LINQ join statement that without AsParallel method has taken 242 ms (milliseconds), the statement with single AsParallel has taken 196 ms and the statement with 2 AsParallel methods has taken 133 ms.

 

The time taken is obvious that there is approximate 20% improvement single AsParallel method and almost double the speed with 2 AsParallel methods.

 

So, which type of statement you want to go for while doing your project?

 

Download the complete code from http://skydrive.live.com. The sample file name is ConAppLINQJoin.rar. My MSN ID is chanmmn@hotmail.com.

About chanmingman

Since March 2011 Microsoft Live Spaces migrated to Wordpress (http://www.pcworld.com/article/206455/Microsoft_Live_Spaces_Moves_to_WordPress_An_FAQ.html) till now, I have is over 1 million viewers. This blog is about more than 50% telling you how to resolve error messages, especial for Microsoft products. The blog also has a lot of guidance teaching you how to get stated certain Microsoft technologies. The blog also uses as a help to keep my memory. The blog is never meant to give people consulting services or silver bullet solutions. It is a contribution to the community. Thanks for your support over the years. Ming Man is Microsoft MVP since year 2006. He is a software development manager for a multinational company. With 25 years of experience in the IT field, he has developed system using Clipper, COBOL, VB5, VB6, VB.NET, Java and C #. He has been using Visual Studio (.NET) since the Beta back in year 2000. He and the team have developed many projects using .NET platform such as SCM, and HR based applications. He is familiar with the N-Tier design of business application and is also an expert with database experience in MS SQL, Oracle and AS 400.
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