Multi-query scheduling for time-critical data stream applications

Many data stream applications, such as network intrusion detection, on-line financial tickers and environmental monitoring, typically exhibit certain "real-time" traits. In such applications, people are interested in strategies that ensure on-time delivery of query results. In this paper, we point out that traditional operator-based query scheduling strategies are insufficient to handle this class of problem. Therefore we choose to approach the issue from a new angle by modeling multi-query scheduling as a job-scheduling problem, a classical problem in real-time computing. By taking advantage of the wisdom in the real-time computing community, we propose several new scheduling strategies and algorithms to enhance the overall data stream query scheduling performance. Through extensive experiments over both real and synthetic data, we identify the important factors for scheduling performance and verify the effectiveness of our approaches.