FIX: CPU usage increases when you run a query that uses a string comparison function on a computer that has many processors after you upgrade to SQL Server 2005 Service Pack 3 or to SQL Server 2008

Consider the following scenario. You install an instance of Microsoft SQL Server 2005 on a computer that has many processors. You upgrade to SQL Server 2005 Service Pack 3 (SP3) or to Microsoft SQL Server 2008. You run a query that uses the Like operator in the WHERE clause or that uses a string comparison function, such as the CharIndex() function. When you run the query many times on multiple connections at the same time, the CPU usage reaches 100 percent, and the server performance decreases significantly.

Note If you run this query in SQL Server 2005 Service Pack 2, the query runs significantly faster.

Cumulative update information

The release version of SQL Server 2008

Important You must install this cumulative update package if your computer is running the release version of SQL Server 2008.

The fix for this issue was first released in Cumulative Update 6. For more information about how to obtain this cumulative update package for SQL Server 2008, click the following article number to view the article in the Microsoft Knowledge Base:Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

SQL Server 2008 Service Pack 1

Important You must install this cumulative update package if your computer is running SQL Server 2008 Service Pack 1.

The fix for this issue was also released in Cumulative Update 3 for SQL Server 2008 Service Pack 1. For more information about this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 fix release. Microsoft recommends that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft SQL Server 2008 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2008 Service Pack 1 hotfix to an installation of SQL Server 2008 Service Pack 1. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.

SQL Server 2005 Service Pack 3

Important You must install this cumulative update package if your computer is running SQL Server 2005 Service Pack 3.

The fix for this issue was also released in Cumulative Update 4 for SQL Server 2005 Service Pack 3. For more information about this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release. Microsoft recommends that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 3 hotfix to an installation of SQL Server 2005 Service Pack 3. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the list of builds that are available after SQL Server 2005 Service Pack 3, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the Incremental Servicing Model for SQL Server, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain SQL Server 2005 Service Pack 3, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the new features and the new improvements in SQL Server 2005 Service Pack 3, visit the following Microsoft Web site: For more information about the naming schema for SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: