关键词: 网构软件, 服务组合, 松弛隔离性, 依赖, 并发控制

Abstract: Internetware is a new software paradigm that facilitates the construction of collaborative applications over Internet， in which applications can be built by composing existing web services. Transaction processing is a key mechanism to make the internetware applications reliable. Due to the autonomy of individual web service and the long-running nature of internetware applications， the strict isolation property among transactions must be relaxed. Thus it becomes a vital problem to ensure the correct concurrent execution of transactional internetware applications under relaxed isolation. In this paper， a novel concurrency control method TSCM-CC（Transactional Service Composition Model-Concurrency Control） is proposed to coordinate the interleaving of concurrent transactions dynamically. First， the dependencies among transactions are classified into several types according to the transactional properties of involved services. Then a set of rules are proposed to confine the forming of dependencies， and their correctness is proved. At last， a distributed coordination protocol is designed to implement these rules. Compared to existing works， the most distinguished advantage of the method is that it can ensure a conflict-serializable execution under relaxed isolation while remain the relaxed atomicity of each transactional internetware application.

Key words: internetware, service composition, relaxed isolation, dependency, concurrency control