| Research Abstract |
In traditional client-server applications, application programs and objects are distributed into clients and servers, respectively. On the other hand, every computer named servant is peer which can have programs and objects in peer-to-peer (P2P) systems. In addition, huge number and various types of computers are interconnected in networks, ranging from high-performance, high-reliable computers like database servers to less-reliable personal computers and mobile stations. It is critical to discuss how to develop and execute reliable applications on databases in P2P systems. In database applications, transactions manipulate objects so as to satisfy ACID (atomicity, consistency, isolation, and durability) properties. In traditional database systems, objects are locked or transactions are timestamped to serialize multiple transactions. If objects in multiple computers are manipulated, the atomic manipulation of multiple computers has to be supported in the two-phase commitment (2PC) proto
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In this research, we discussed a novel type of agent model, transactional agent model to manipulate objects in multiple computers with types of commitment constraints. A transactional agent is defined to be a mobile agent which moves around computers and locally manipulates objects in one or more than one computer with type of commitment constraint. In addition, an agent negotiates with another agent if the agents manipulate a same object in a conflicting manner. Through the negotiation, each agent autonomously makes a decision on whether the agent holds or releases the objects. A transactional agent autonomously finds another destination computer if a computer where the agent to move is faulty. In this research, we discussed how to implement transactional agents in Java Aglets and Oracle database systems. We showed the evaluation of the mobile agent-based transaction systems for applications. If Aglets classes are a priori loaded, the transactional agents can manipulate object servers more shortly than the traditional client-server model. Less
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