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Query that has an "order by" clause runs slowly in the .NET Framework 4.0 if WCF Data Services exposes a table that has a clustered index

Consider the following scenario:
  • You create a table in an instance of Microsoft SQL Server. This table has a clustered index.
  • The table is exposed by Windows Communication Foundation (WCF) Data Services in the Microsoft .NET Framework 4.0.
  • You run a query for the WCF Data Services. The query has an order by clause and a $top, $skip, or $skiptoken option.
In this scenario, the query may run slower than expected.
This issue occurs because of an error in WCF Data Services.

When the server that runs WCF Data Services uses its own method to determine the order of metadata keys, the defined order in the clustered index is not preserved. Therefore, sort operations do not use the clustered index, and the query runs slowly.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


To apply this hotfix, you must have the .NET Framework 4.0 installed.

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfix.

File Information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

For all supported x86-based versions of Windows XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, of Windows 7, and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform,34417-Nov-201003:51x86
For all supported x64-based versions of Windows XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, of Windows 7, and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform,34417-Nov-201003:5164,34417-Nov-201003:51x86
For all supported IA-64-based versions of Windows Server 2003, of Windows Server 2008, and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform,34417-Nov-201003:51IA-64,34417-Nov-201003:51x86

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about how to add query options to a data service query for WCF Data Services, visit the following Microsoft Developer Network website:


Article ID: 2425165 - Last Review: 01/18/2011 09:16:00 - Revision: 2.0

Microsoft .NET Framework 4

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