WorldFlow: Workflow Management over the Web


In order to exploit the potential of the Web, companies offering workflow products now provide a Web interface to WFMSs. This allows both the employees and the customers of a company to interact with the WFMS through the Web. Employees can access their `to-do' list via a Web browser instead of using a special client as in traditional WFMSs. Thus employees can interact with the WFMS wherever they are located as long as they have access to a Web browser. Also, when a customer submits an order via a Web form, an appropriate workflow is automatically triggered to handle the customer order. However these WFMSs lack facilities for workflows whose steps directly access and update data from Web servers. In short, they support customer-to-business transactions over the Web but not business-to-business transactions. The latter is necessary to support workflows whose steps are business transactions executed by Web servers.

It would be more beneficial to provide the WFMS with additional knowledge about the Web, its protocols and data format such that workflows can directly access information by interacting with Web servers. This will allow companies to automate their business processes on the Web by allowing steps to automatically query/update information from Web servers located both within and outside the organization. The additional knowledge required is provided by the workflow system developer and the workflow designer. Combining workflow management and Web technologies in this manner will offer immense benefits for conducting business over the Web. In addition to customer-to-business transactions, workflows consisting of business-to-business transactions can be executed over the web. For example, it will be possible to implement Web workflows that handle supply chain management where a group of suppliers and customers distributed around the world cooperate as trading partners. The formation of such a virtual enterprise would make it possible to implement JIT (Just In Time) method of inventory control to save money on inventory, warehousing and handling costs. Thus a company manufacturing a product can use Web workflows to place orders for the individual components needed to make the product immediately after it receives an order for the product. Steps of Web workflows will use the same Web interface provided by the supplier for its customers. To make Web workflows feasible, it is necessary to develop WFMSs that address the special requirements of conducting business over the Web and making efficient use of Web technology.

This work focuses on two of the problems that arise in implementing workflows on the Web, namely (i) dealing with the unreliability of the Web in the form of server/network failures and delays and (ii) improving efficiency. We first present a protocol to ensure that an update request is processed by a server exactly once, despite network/server failures. This will facilitate the reliable execution of workflows on the Web. Secondly, to ameliorate the effects of network delays and failures, we develop an optimizer that compiles a workflow schema and parallelizes the steps in the workflow to the maximum possible extent. The optimizer uses the data and control flow information associated with the workflow schema to perform this. Parallelizing workflows is a generally useful technique, but it is especially important because of the unreliability of the Web. Thirdly, to improve efficiency, we offer a multi-part solution that utilizes emerging Web technologies like Java and standard enhancements that have been proposed for the Web infrastructure, e.g., for the HTTP protocol by the Internet Engineering Task Force (IETF). Our solution consists of (i) providing some ``intelligence'' at the client using Java/JavaScript, (ii) prefetching of steps and (iii) batching of steps. All these techniques are geared towards reducing the number of messages exchanged (both within the organization and to other organizations through the organizations gateway) and reducing the load at the workflow-engine. Finally, we have designed an architecture for implementing , our workflow management system for the Web. To demonstrate the viability and benefits of our ideas, we are developing a prototype of the WorldFlow system so as to experiment with our techniques on some real world examples.


Narain Gehani, Mohan U. Kamath, Daniel Lieuwen and Krithi Ramamritham,
"WorldFlow: Workflow Management over the Web", (forthcoming)

Also check out the ongoing CREW Project and other work we have done in Workflows.

Back to the Database Systems Home Page

If you have any comments on this page or need further information, please send your mail to
Last Update: 4 March 1997