Error-resilient concurrency control for transaction management in wireless broadcasting environments

Abstract

In order to provide information to numerous concurrent clients, broadcast delivery is attractive for use in a number of emerging database applications because it is independent of the number of users the applications are serving. However, the distribution of data over a broadcast channel cannot be reliable because an acknowledgement explosion phenomenon is raised when a reliable communication protocol of retransmissions and acknowledgements is applied to the broadcast channel. Therefore, a concurrency control scheme in wireless broadcasting environments should overcome broadcast errors because they are unavoidable when data is distributed over the broadcast channel. This thesis proposes a novel concurrency control scheme, called error-resilient concurrency control (RCC), which exploits broadcast delivery but is not vulnerable to broadcast errors in the wireless broadcasting environments. The performance of RCC was evaluated with an analytical model focusing on the effects of broadcast errors on concurrency control. The performance was also measured with a simulation model. The analytical results conformed to those of the simulation model. The results show that RCC is not only applicable to a broad range of broadcast error rates, but it also achieves better performance than the two compared models, the optimistic concurrency control scheme and the certification reports scheme.