Transactional Workflow Technology Research

Workflow management systems are used to coordinate and automate business processes. Since process instances often access shared persistent data and run concurrently, they are subject to transactional properties. In order to enhance the reliability of WfMS and to ensure the correctness of the complex business processes in distributed and heterogeneous environment, it is important to guarantee those transactional properties. In the early 1990's, the term transactional workflow was introduced to clearly recognize the relevance of transactions to workflows. The development of transactional workflow technology is of great importance for pushing workflow technology into practice. Transactional workflow technology has been a research focus on both transaction management and workflow areas.To solve existing problems, we propose a process model TFPM of the transactional workflow, which introduces the nesting structure, give the definition of this model, and the definition of the isolation sphere, the types of the failure recovery, which support the concurrency control based on the isolation sphere and the failure recovery based on the process execution history. Analyze the concurrency phenomena of the workflow management system. Propose a scheduling algorithm, which can avoids the lost update and the dirty read phenomena base on the appropriate setting of the isolation sphere and the isolation property, the user can set the isolation level based on the business process, and improve the concurrency of the process instance. Analyze the causes of the workflow system's failures, compartmentalize the type of these failures, and then propose the failure recovery algorithm which based on the process execution history. This algorithm can reduce the sphere of the compensation. Design, a prototype of the transactional workflow system named TFlow, which solves the problem of the existing workflow products or prototypes. This prototype provides integration of concurrency scheduler and workflow engine, TFlow is a framework that provides concurrency and recovery correctness guarantees for the execution of transactional workflow.Our research on transactional workflow model, concurrency control, failure recovery and transactional workflow prototype provides a new approach and an new idea for research on transactional workflow.