Necessary and Sufficient Checkpoint Selection in Grid Workflow Systems

In grid workflow systems, existing representative checkpoint selection strategies, which are used to select checkpoints for verifying fixed-time constraints at run-time execution stage, often select some unnecessary checkpoints and ignore some necessary ones. Consequently, overall temporal verification efficiency and effectiveness can be severely impacted. In this paper, we propose a new strategy that selects only necessary and sufficient checkpoints dynamically along grid workflow execution. Specifically, we introduce a new concept of minimum time redundancy as a key reference value for checkpoint selection. We also describe how to obtain minimum time redundancy dynamically along grid workflow execution and investigate its relationships with fixedtime constraint consistency. Based on these relationships, we present our strategy and rigorously prove its necessity and sufficiency. The quantitative evaluation further demonstrates that compared to existing representative strategies, our strategy can improve overall temporal verification efficiency and effectiveness significantly. Covered topics: Process verification and validation, Workflow management systems