Summary

The interfaces that make up the memory manager enable a host to control closely how the CLR uses memory in a process. These interfaces effectively form an abstraction layer between the CLR and the operating system by enabling the host to provide the basic memory management primitives for which the CLR typically relies on the operating system. By implementing a memory manager, a host can control basic functions such as the use of virtual memory and the management of heaps. SQL Server 2005 uses a memory manager to ensure that memory allocated by the CLR doesn't cause SQL Server to exceed the amount of memory it is configured to use.

Hosts can also affect the CLR's use of memory using the interfaces that constitute the garbage collection manager. The ICLRGCManager interface enables the host to optimize how the garbage collector functions by partitioning the garbage collection heap in ways that best fit the memory usage patterns of the host. Configuring the garbage collector requires extensive iteration and testing. It's surprisingly easy to hinder performance inadvertently if you haven't done sufficient benchmarking.