Improving Web Server Performance by Caching Dynamic Data

Abstract

Dynamic Web pages can seriously reduce the performance of Web servers. One technique for improving performance is to cache dynamic Web pages. We have developed the DynamicWeb cache which is particularly wel l-suited for dynamic pages. Our cache has improved performance signi cantly at several commercial Web sites. This paper analyzes the design and performance of the DynamicWeb cache. It also presents a model for analyzing overal l system performance in the presence of caching. Our cache can satisfy several hundred requests per second. On systems which invoke server programs via CGI, the DynamicWeb cache results in near-optimal performance, where optimal performance is that which would be achieved by a hypothetical cache which consumed no CPU cycles. On a system we tested which invoked server programs via ICAPI which has signi cantly less overhead than CGI, the DynamicWeb cache resulted in near-optimal performance for many cases and 58% of optimal performance in the worst case. The DynamicWeb cache achieved a hit rate of around 80% when it was deployed to support the ocial Internet Web site for the 1996 Atlanta Olympic games.