C3: Concurrency control on continuous queries over moving objects

Moving object management approaches, especially continuous query processing techniques, have attracted significant research effort due to the broad usage of location-aware devices. However, little attention has been given to designing concurrency control protocols for continuous query processing. Existing concurrency control protocols for spatial indices are based on a single indexing tree, while popular continuous query processing approaches require multiple indices. In addition, continuous monitoring combined with frequent location updates challenges the development of serializable isolation for concurrent index operations. This paper proposes an efficient concurrent continuous query processing approach C3, which fuses scalable continuous query processing methods with lazy update techniques on R-trees. The proposed concurrency control protocol, equipped with intra- and inter-index protection, assures serializable isolation, consistency, and deadlock-freedom. The correctness of the proposed protocol is theoretically proven, and the experiment results demonstrated its scalability and efficiency.