Process synchronization in workflow management systems

Abstract

Workflow management systems automate the execution of business processes allowing the concurrent execution of multiple process instances. Existing systems do not provide a mechanism to guarantee correct concurrent execution and, as a result, it is not possible to coordinate and synchronize different process instances. Part of the problem is that conventional techniques are not entirely suitable for workflow environments. In databases, locks are the basic mechanism. In operating systems, this is achieved using semaphores or monitors. Neither of these approaches is appropriate for workflow applications. A method is proposed to enforce correct interleavings and guarantee mutual exclusion, as defined by the user, between concurrent workflow processes. The proposed protocol takes advantage of the semantic constructs associated with workflow management to solve some complex problems such as dealing with inherited restrictions and the coarse granularity of workflow specifications.