A mobile transaction processing system to improve concurrency in mobile database

Mobile Database System (MDS) is a distributed client/server system where clients can move around freely while performing their data processing activities in connected, disconnected, or intermittent connected mode [7]. It can process debit/credit transactions such as pay utility bills, airline reservations, and other transactions without being subject to any geographical constraints [8]. Since there is no MDS type of system available, it is difficult to identify the transaction volume at mobile units, however, the present information processing needs and trends in e-commerce indicate that transaction workload at each mobile unit could be high and MDS would be a useful resource to most of the organizations. Although MDS is a distributed system based on client/server paradigm [8], it differs from conventional centralized or distributed systems in transaction management schemes (concurrency control, database recovery, query processing, etc.), different logging scheme, different caching schemes, etc [8]. For example, in MDS or in any distributed system, a number of activities related to transactions´ execution, such as transaction arrival at client or at a server, transaction fragmentation and their distribution to relevant nodes for execution, dispatch of updates made at clients to the server, migration of a mobile unit to another cell (handoff), etc., have to be logged for recovery.