Caching
Caching is a key technique to reduce hardware and administrative costs and to improve response time. Caching applies to the dispatcher or edge server, the Web presentation server, the Web application server, the network, the existing business applications, and the database. The goal is to improve performance and scalability by reducing the length of the path traversed by a request and the resulting response, and by reducing the consumption of resources by components.
Caching techniques can be applied to both static and dynamic Web pages. A powerful technique to improve performance of dynamic content is to asynchronously identify and generate Web pages that are affected by changes to the underlying data. Once these changed pages are generated, they must be effectively cached for subsequent data requests. There are several examples of intelligent caching technologies that can significantly enhance the scalability of e-business systems.
The key issue with caching dynamic Web pages is determining what pages should be cached and when a cached page has become obsolete.
Caching is a technology that has several products available. One such product, the Caching Proxy, is part of the Edge Components available with IBM WAS Network Deployment V5.1. This chapter discusses in high-level terms some key concepts without subscribing to one product or another. See also:
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