FIX: Error message when you call a table valued function that uses a common language runtime (CLR) assembly in SQL Server 2005: "AppDomain <ApplicationDomain> is marked for unload due to memory pressure"

Consider the following scenario. In Microsoft SQL Server 2005, you create a common language runtime (CLR) assembly. Then, you create a table valued function that uses the CLR assembly. In this scenario, a memory leak may occur when you call the table valued function repeatedly. If you monitor the #GC Handles counter of the .NET CLR Memory object in System Monitor (Perfmon.exe), you find that the number of garbage collection handles keeps increasing.

Eventually, the CLR assembly stops working, and the following error message is logged in the SQL Server 2005 error log:

The compiled execution plan of the CLR assembly is deleted from the cache on the SQL Server side. However, the corresponding information about the table valued function is not deleted from the cache on the CLR assembly side. Therefore, the CLR creates a new handle when you call the table valued function for the second time. The CLR creates a new handle instead of using the original handle. Eventually, the application domain is unloaded because of memory pressure.

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 2005 Service Pack 2, 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 2 hotfix to an installation of SQL Server 2005 Service Pack 2. 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 what files are changed, and for information about any prerequisites to apply the cumulative update package that contains the hotfix that is described in this Microsoft Knowledge Base article, click the following article number to view the article in the Microsoft Knowledge Base:

For more information about the list of builds that are available after SQL Server Service Pack 2, 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 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the new features and the improvements in SQL Server 2005 Service Pack 2, 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: