Assume that there are many connections to a Microsoft SQL Server 2008 R2 database. These connections run the same query together with different query options. In this situation, SQL Server 2008 R2 experiences slow performance.
This issue occurs because the different query plans for the different query options conflict with each other out of the plan cache. This results in recompilation and high CPU usage.
Cumulative update information
Cumulative Update 8 for SQL Server 2008 R2 Service Pack 2
The fix for this issue was first released in Cumulative Update 8. For more information about how to obtain this cumulative update package for SQL Server 2008 R2 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:
2871401 Cumulative update package 8 for SQL Server 2008 R2 Service Pack 2Note 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 R2 Service Pack 2 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:
2730301 The SQL Server 2008 R2 builds that were released after SQL Server 2008 R2 Service Pack 2 was released
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.