Exploiting temporal query behavior for improving result cache accuracy in web search engines

In Web Search Engines responding to the user queries in a timely fashion is an important requirement. One of the integral techniques to improve the response time of a search engine is caching. By storing different types of information in a fast access memory storage, caching achieves a higher availability and better response times for the search engine. Due to anonymous and global access pattern of the queries, search engines are often considered timeless frameworks. That is, search engine sites constantly respond to queries that are submitted all around the world at an almost constant pace throughout the day. During our studies, we evaluate this phenomenon and come to the conclusion that each of the data centers, which in cooperation form the general infrastructure of a general purpose search engine in fact realizes high levels of query temporality. In this work, we aim to apply and exploit the temporal behavior of the submitted queries to improve the cache accuracy by proposing a new caching architecture. To this end, we improved the state-of-the-art result caching framework Static-Dynamic Cache (SDC) and modified it in order to incorporate query temporality. Our experiments show that the proposed caching framework improves the hit rate of a result cache up to 3%, which is roughly 25% of the possible room for improvement.