Design of a Sequential Tentative Hold Protocol for Efficient Coordination of Web Services Transaction

Web services technology enables integration of geographically distributed services and provides efficient and flexible coordination models for integration. The tentative hold protocol (THP) allows Web service transactions to reserve resources by applying tentative holds on them, which provides increased flexibility. However, the simple policy of THP is of shortage in maximizing resource utilization in transaction coordination. In this paper, we propose a sequential tentative hold protocol (S-THP) to overcome this shortage. It records the sequence of resource accessing when hold requests are submitted, and locks only indispensable resources instead of all resources during the transaction. By sequentially locking and accessing the resources, S-THP is able to achieve better resource utilization and efficiency. A detailed comparison is carried out to demonstrate the advantage of the proposed protocol. Finally, it can be concluded from the simulations that S-THP provides coordination with better efficiency and flexibility.