A new prefetch cache scheme

The criterion that existing prefetch schemes apply in prefetching documents from the origin servers into a proxy Web server is usually the probability of each document being accessed in the near future or the popularity of the document. This criterion is not optimum in minimizing the average access latency or maximizing the average hit probability because the factors that affect the latency and the hit probability also include the response time and the updating cycle of the documents. We derive expressions for the average latency, hit probability, cache capacity and required bandwidth for a general prefetch scheme. A new prefetch scheme that combines access probability, response time and updating cycle to determine the lowest average latency or the highest hit probability is proposed. Finally, some numerical results are presented. The required parameters of the prefetch scheme can be simply derived from the log data of the cache. Thus, our scheme can be implemented in practice.