Cache refresh policies

The use of caching requires a refresh policy that prevents the executing application from using out-of-date versions of objects in the caches. Proxy servers can be scheduled to refresh their caches automatically at a prescribed interval or on demand at a particular time. All refresh policies are based on actions started in the proxy server, either because an object has expired or through scheduled processes for checking the versions of server objects. There are no dynamic updates of objects in the proxy when the objects are updated on the Web server. Therefore, depending on the specific system environment and the detailed analysis of the proxy server features, the issue of consistency between the proxy and the server must be resolved, and its solution built as part of the application process.