Workflow Recovery with Ensuring Task Dependencies Presented by Yajie Zhu March 08, 2005

Workflow management systems (WFMS) A system or set of tools that completely defines, manages and executes workflow. A workflow consists of a set of tasks that have to be performed in a sequence. A task is any specific unit of computation that performs some useful function in a system. (e.g., a specific application program, or a database transaction.) Task dependencies are a set of constraints specified among tasks in a workflow. (e.g., a certain task must be aborted if another task is aborted)

Motivation In order to coordinate the execution various tasks in a workflow, task dependencies are enforced during normal execution. When a system crash or failures occurs, the workflow will be left in an inconsistent stage. To recovery an inconsistent workflow, a lot of researchers work on restoring consistency by removing the effects of partially executed tasks. These approaches fail to address how to ensure task dependencies during workflow recovery.

An new approach Analysis the different kinds of task dependencies present in a workflow, and show how these task dependencies impact the recovery process. Discuss what information is needed and how to use it to performance a recovery process. Based on a specific workflow scheduler, I will propose an automated workflow recovery algorithm that ensures the satisfaction of task dependencies and restores consistency as well.