Freshness-Aware Scheduling of Continuous Queries in the Dynamic Web

The dynamics of the Web and the demand for new, active services are imposing new requirements on Web servers. One such new service is the processing of continuous queries whose output data stream can be used to support the personalization of individual user’s web pages. In this paper, we are proposing a new scheduling policy for continuous queries with the objective of maximizing the freshness of the output data stream and hence the QoD of such new services. The proposed Freshness-Aware Scheduling of Multiple Continuous Queries (FAS-MCQ) policy decides the execution order of continuous queries based on each query’s properties (i.e., cost and selectivity) as well the properties of the input update streams (i.e., variability of updates). Our experimental results have shown that FAS-MCQ can increase freshness by up to 50% compared to existing scheduling policies used in Web servers.