Policy Server Guides › Policy Server Administration Guide › Scaling Your SiteMinder Environment › How to Determine When to Add Policy Servers › Modify the Number of Connections Provided by Policy Servers › How the Policy Server Threading Model Works

How the Policy Server Threading Model Works

The Policy Server worker thread pool consists of two separate thread pools that independently process High Priority and Normal Priority messages. A reactor thread receives all incoming Web Agent requests and depending on the message type, passes them to either the High Priority or Normal Priority queue. High Priority messages include Agent connection requests. Normal Priority messages include user messages, such as authentication and authorization requests.

• High Priority messages—the default number of worker threads in the thread pool available for High Priority messages is five and the maximum number is 20. You can change the default value by adding and setting the PriorityThreadCount registry key.
• Normal Priority messages—the default number of worker threads in the thread pool available for Normal Priority messages is eight. You can add additional worker threads by modifying the Maximum Threads setting field on the Data tab in the Policy Server Management Console.

Note: For more information, see the Policy Server Management Console Reference in this guide.

The maximum number of worker threads available to Normal Priority messages depends on the operating system on which the Policy Server is installed and on the amount of memory available to the system. See your vendor-specific documentation for more information about thread usage.

Varying the size of the thread pool to improve performance is an iterative process that is largely dependent on the specific environment in use.