Prefetching query results and its impact on search engines

Abstract

We investigate the impact of query result prefetching on the efficiency and effectiveness of web search engines. We propose offline and online strategies for selecting and ordering queries whose results are to be prefetched. The offline strategies rely on query log analysis and the queries are selected from the queries issued on the previous day. The online strategies select the queries from the result cache, relying on a machine learning model that estimates the arrival times of queries. We carefully evaluate the proposed prefetching techniques via simulation on a query log obtained from Yahoo! web search. We demonstrate that our strategies are able to improve various performance metrics, including the hit rate, query response time, result freshness, and query degradation rate, relative to a state-of-the-art baseline.