Execution Recovery in Transactional Composite Service

In the composite service which runs for a long time under the heterogeneous and loose-coupled circumstance, the failure of service tends to occur. The transaction and recovery mechanism is urgently needed in order to guarantee the end-to-end QoS of the workflow and satisfy the user requirement. In this paper we address the composite service recovery issue in the way of substitution with the consideration of QoS constraint, based on our previous research work of the transactional construction and processing rules and the global optimization service selection algorithm, TSSA. Firstly, the service execution graph (SEG) is introduced and a service execution solution selection algorithm is proposed to choose one from the solution set of TSSA which has the highest success rate of recovery. Then, the concepts of execution backup path and switch cost are introduced and a search algorithm is presented to search for the optimal backup path when current service failure occurs. Meanwhile, a local induction algorithm based on positive feedback is described which could rapidly construct an transactional execution path when no backup execution path can be found in SEG and also guarantees the transactional constraint of composite service. Finally, experimental results show the recovery algorithm proposed in this paper is efficient and has high reliability.