Web services have become a dominating technology for business integration. For operation reliability and robustness, transactional support is an important issue for Web service system design and development. Yet, most existing Web services protocols, like WS-BPEL which sticks to the compensation-based recovery strategy, only provide very limited supports for Web services in certain circumstances. As Web service systems are scaling up, more advanced transactional supports beyond traditional compensation-based solutions are required to catch up with the increasing complexity of composite Web services. This chapter looks into the problem of transactional support for composing and scheduling those Web services that may have different transactional properties. The transactional properties of workflow constructs, which are fundamental to the composition of Web services, are thoroughly investigated. The concept of connection point is introduced to derive the transactional properties of composite Web services. The scheduling issue of composite Web services is also discussed.
Reliable Composite Web Services Execution: Towards a Dynamic Recovery Decision