Large web search engines are now processing billions of queries per day. Most of these queries are interactive in nature, requiring a response in fractions of a second. However, there are also a number of important scenarios where large batches of queries are submitted for various web mining and system optimization tasks that do not require an immediate response. Given the significant cost of executing search queries over billions of web pages, it is a natural question to ask if such batches of queries can be more efficiently executed than interactive queries.

In this paper, we motivate and discuss the problem of batch query processing in search engines, identify basic mechanisms for improving the performance of such queries, and provide a preliminary experimental evaluation of the proposed techniques. Our conclusion is that significant cost reductions are possible by using specialized mechanisms for executing batch queries in Web search engines.