Requests for dynamic and personalized content have increasingly become a significant part of Internet traffic, driven both by a growth in dynamic web services and a "trickle-down" effect stemming from the effectiveness of caches and content-distribution networks at serving static content. To efficiently serve this trend, several server-side and cache-side techniques have recently been proposed. Although such techniques, which exploit different forms of reuse at the sub-document level, appear promising, a significant impediment to their widespread deployment is (1) the absence of good models describing characteristics of dynamic web content, and (2) the lack of effective synthetic content generators, which reduce the effort involved in verifying the effectiveness of a proposed solution.

Requests for dynamic and personalized content have become an important part of current-day Internet traffic; however, traditional caching architectures are not wellsuited to cache such content. Several recently proposed techniques, which exploit reuse at the sub-document level, promise to address this shortcoming, but require a better understanding of the workloads seen on web sites that serve such content. In this paper, we study the characteristics of a mediumsized personalized web site, NYUHome, which is a customizable portal used by approximately 44,000 users from the New York University community. Our study leverages detailed server-side traces of client activity over a two-week period in February 2002, obtained by instrumenting the NYUHome server. The paper presents statistics on document composition, personalization behavior, server-side overheads, and clientperceived request latencies. We then use these statistics to derive general implications for efficient caching and edge generation of dynamic content in the context of our ongoing CONCA project. Our study verifies both the need for and likely benefit from caching content at sub-document granularity, and points to additional opportunities for reducing client-perceived latency using prefetching, access prediction, content transcoding, and migrating channel generation functionality to the edge. 1

Over the last few years, the World Wide Web has transformed itself from a static content-distribution medium to an interactive, dynamic medium. The Web is now widely used as the presentation layer for a host of on-line services such as e-mail and address books, e-cards, e-calendar, shopping, banking, and stock trading. As a consequence, HTML files are now typically generated dynamically after the server receives the request. From the Web-site providers ’ point of view, dynamic generation of HTML pages implies a lesser understanding of the real capacity and performance of their Web servers. From the Web developers ’ point of view, dynamic content implies an additional technology decision: the Web programming technology to be employed in creating a Web-based service. Since the Web is inherently interactive, performance is a key requirement, and often demands careful analysis of the systems. In this paper, we compare four dynamic Web programming technologies from the point of view of performance. The comparison is based on testing and measurement of two cases: one is a case study of a real application that was deployed in an actual Web-based service; the other is a trivial application. The two cases provide us with an opportunity to compare the performance of these technologies at two ends of the spectrum in terms of complexity. Our focus in this paper is on how complex vs. simple applications perform when implemented using different Web programming technologies. The paper draws comparisons and insights based on this development and performance measurement effort. 1.

Proxy caching and content distribution networks (CDNs) are two major approaches to improve Web application performance. Unfortunately, we have witnessed the inefficiency of them to the rapid growth of uncacheable HTTP content, resulting from ever-increasing dynamic Web services, cache busting technologies, and the emergency of various HTTP-based applications. Although several approaches have been proposed for caching fragment-based dynamic Web content, such as edge side include and client-side include, we believe that a general understanding of the characteristics of uncacheable HTTP content is of great importance to the future of HTTP-based content caching and delivery. In this paper, we characterized...