Detecting Data Flow Errors in Workflows: A Systematic Graph Traversal Approach

Abstract

When designing a workflow, it is customary practice to create the control flow structure first and to ensure its correctness. Information about the flow of data is introduced subsequently into the workflow and its correctness is independently verified. Improper specification of data requirements of tasks and XOR splits can cause problems such as wrong branching at XOR splits and the failure of tasks to execute. Here we present a graph traversal algorithm called GTforDF for detecting data flow errors in a workflow that is free of control flow errors, and illustrate its operation on two realistic workflows with interconnected loops. Our approach extends and generalizes data flow verification methods that have been recently proposed. It also makes use of the concept of corresponding pairs lately introduced in control-flow verification. It thus has the potential for development into a unified algorithmic procedure for the concurrent detection of control flow and data flow errors.

Keywords: data flow algorithms, lost data, missing data, redundant data, corresponding pair