Periodically updating sliding window join algorithms over data streams

According to the updating granularity,two kinds of sliding window are defined: continuously updating sliding window and periodically updating sliding window. All the existed sliding window algorithms over data streams are designed for continuously updating sliding window, which are not suitable for periodically updating sliding window. To address this problem, three effective join algorithms for periodically updated sliding window, BSHJ, BSNLJ and BSNHJ, are proposed. Theoretical analysis and experiment results show that BSNHJ achieves optimal performance.