ON STRATEGIES FOR ALLOCATING REPLICAS OF MOBILE DATABASES

Mobile databases will play an important role in mobile computing envir onment, to provide data storing and data retrieval functionalities whi ch are needed by most applications. In mobile computing environment, t he wireless communication poses some problems, which require us to min imize its use. Replication is a database technique that is commonly us ed to fulfill the requirement in minimizing network usage. In this pap er, we propose two replica allocation strategies, called primary-copy tracking replica allocation (PTRA) and user majority replica allocatio n (UMRA), which are better suited to the mobile computing environment. Their proposals are intended to cope with cost performance issues in data replication due to user mobility in mobile computing environment. To investigate their effectiveness, we provide access cost analysis a nd comparison on these strategies and the static replica allocation (S RA) strategy. We show that our proposed strategies outperform the SRA strategy when user mobility (inter-cell movement) is relatively low as compared with data access rate.