User-Defined Atomicity Constraint: A More Flexible Transaction Model for Reliable Service Composition

Abstract

Transaction is the key mechanism to make service composition reliable. To ensure the relaxed atomicity of transactional composite service (TCS), existing research depends on the analysis to composition structure and exception handling mechanism. However, this approach can not handle various application-specific requirements, and causes lots of unnecessary failure recoveries or even aborts. In this paper, we propose a relaxed transaction model, including system mode, relaxed atomicity criterion, static checking algorithm and dynamic enforcement algorithm. Users can define different relaxed atomicity constraint for different TCS according to the specific application requirements, including accepted configurations and the preference order. The checking algorithm determines whether the constraint can be satisfied. The enforcement algorithm monitors the execution and performs transaction management works according to the constraint. Compared to existing work, our approach is flexible enough to handle complex application requirements and performs the transaction management works automatically. We apply the approach into web service composition language WS-BPEL and illustrate the above advantages through a concrete example.