Options: a way for achieving failure atomicity in the WorkMan system

摘要

WorkMan is a workflow prototype system in which considerable attention is paid for workflows' transactional properties and the utilization of the services provided by database systems supporting SQL. Particularly the system provides different approaches for workflows' failure atomicity: likewise most other workflow systems it provides compensation mechanism, but besides this it provides options. Through options the problems related to dirty data can be avoided: instead of making dirty updates, workflows try to acquire options. An option is a certification of the success of a possible later update. If the workflow will commit, then the options are realized, and otherwise canceled. Options are implemented by installing appropriate constraints in the database. Two variations of options are introduced, called public options and internal options. They differ in whether the effects of g ranted options are visible to other concurrent activities.