Maintaining data consistency of read-only transactions in broadcast environments

Abstract

In the mobile computing environment, the majority of applications are disseminating information to a large number of clients. In old days, mobile clients used to access their interested data in the form of pull-based data delivery. However, as the scale of mobile clients increases tremendously, the performance for clients will be degraded. This leads to another form of data delivery which is broadcast. Although the broadcast data delivery can maintain mobile clients’ performance, this form of data delivery poses some difficulties and problems. Due to concurrent execution of update transactions and broadcast of data items, mobile clients may see the inconsistency of data values if they fetch their interested data in different cycles. This project focuses on ensuring data consistency of read-only transactions when data items are being updated. Two major methods will be presented for maintaining data consistency of read-only transactions without contacting server. A series of experiments will be carried out to evaluate their efficiency. Those simulation results will be used to understand the basic tradeoffs in solving the problem. In addition, cache is also used to improve the system performance.