A workflow management system (WFMS) facilitates the coordinated execution of applications (steps) that comprise a business process (workflow) across distributed nodes. State-of-the-art WFMSs do not have adequate support for handling various correctness and failure handling requirements of workflows. Different correctness requirements arise due to the dependencies between steps that access shared resources. Failure of steps in a workflow and system failures can cause data inconsistencies if handled improperly. Scalability is also a problem in current WFMSs since they use a centralized workflow control architecture that can easily become a performance bottleneck. In this thesis, we have developed the concepts and infrastructure necessary to address the above issues. To handle dependencies across workflows we have developed techniques for expressing and handling mutual-exclusion, relative ordering and rollback dependency requirements across workflow instances. To handle failure of steps within a workflow, we have proposed a new opportunistic scheme that avoids unnecessary compensations and re-executions when workflows are rolled back partially and re-executed. To handle system failures we have designed suitable logging schemes and protocols. To achieve scalability while satisfying the different correctness and failure handling requirements, we have enhanced our techniques to work on parallel and distributed workflow control architectures. To realize the above concepts, we have designed a workflow specification language, a two stage compiler and a rule-based run-time system. A workflow designer specifies the workflow schema and the resources accessed by the steps from a global database of resources. The two stage workflow compiler determines data dependencies and translates the high level schema into a uniform set of rules. The run-time system interprets these rules and executes the workflows in accordance with their requirements under central, parallel and distributed workflow control. To demonstrate the usefulness and practicality of our approach, we have implemented a prototype system that can offer better correctness, performance and functionality than state-of-the-art WFMSs.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-3052 |
| Date | 01 January 1998 |
| Creators | Kamath, Mohan Umesh |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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