Workkow History Management

A work ow history manager maintains the information essential for work ow monitoring and data mining as well as for recovery and authorization purposes Certain characteristics of work ow systems like the neces sity to run these systems on heterogeneous autonomous and distributed environments and the nature of data prevent history management in work ows to be handled by the clas sical data management techniques like distributed DBMSs We further demonstrate that multi database query process ing techniques are also not appropriate for the problem at hand In this paper we describe history management i e the structure of the history and querying of the history in a fully distributed work ow architecture realized in conformance with Object Management Architecture OMA of OMG By fully distributed architecture we mean that the scheduler of the work ow system is distributed and in accordance with this the history objects related with activities are stored on data repositories like DBMSs les available at the sites involved We describe the structure of the history objects determined according to the nature of the data and the processing needs and the possible query processing strategies on these objects using the Object Query Service of OMG We then present the comparison of these strategies according to a cost model developed