Chapter 5: How WebSphere Caches Dynamic Content for High-Volume Web Sites

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Overview

Executive summary: Web site visitors expect increasingly quick response time. Web site designers are always trying to improve response time and, at the same time, provide content that personalizes each visit and attracts visitors to become regular customers. Sooner or later customer expectations and designer efforts to meet them come into conflict as a result of severe network and server bottlenecks caused by the constant need to retrieve data from the back-end Web application and database servers. This is especially true for high-volume Web sites.

Server-side caching techniques have long been used to improve Internet performance of Web applications. In general, caching improves response time and reduces system load. Until recently, caching has been limited to static content, which is content that rarely changes. Opportunities to improve performance are greatest when dynamic content is also cached. Dynamic content is content that changes frequently, or data that is personalized. And, caching dynamic content requires proactive and effective invalidation mechanisms, such as event-based invalidation, to ensure the freshness of content. Implementing a cost effective caching technology for dynamic content is essential for the scalability of today's dynamic, data-intensive, e-business infrastructures.

This chapter introduces the dynamic cache service that comes with WebSphere Application Server, Version 5.0. WebSphere Application Server is the first server to include a dynamic cache service that is not only comprehensive and easily implemented, but also compatible with existing caching mechanisms. Using WebSphere Application Server dynamic cache service to cache dynamic content can reduce server-side bottlenecks and maximize system resources, thus boosting performance and reducing infrastructure cost. Given customer expectations and the need to retain them and attract more, dynamic content caching with WebSphere Application Server can be a competitive advantage for high-volume Web sites.

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