Learning WCF

Summary

In this chapter, you learned about instancing modes, concurrency modes and synchronization, as well as throttling behaviors for WCF services. You learned how to apply PerCall, PerSession, and Single instancing modes and the resulting effect on service object allocation; the implications of application sessions, transport sessions, reliable sessions, and secure sessions where exceptions and faults are concerned; how to throttle access for concurrent requests, service instances, and session allocation; and the impact of sessions on load balancing and failover scenarios. Some general recommendations you can take away from this chapter are:

• Use PerCall services whenever possible.

• Avoid PerSession concurrency mode for large-scale deployments.

• When PerSession services are required, try to use Single concurrency mode for synchronization. Require session-capable bindings in the service contract.

• Avoid Single concurrency mode for large-scale server deployments.

• When Single concurrency mode is required and clients are multithreaded, apply custom synchronization only if necessary to increase throughput.

• Always check the proxy state to ensure the server channel has not faulted.

• Try to throw FaultException derivatives from services to avoid unnecessarily faulting the server channel.

• Set throttling behaviors to yield as close to 300 requests per second for a single host process as possible and to ensure callers are able to acquire new sessions.

• Pay close attention to performance counters watching ...