The Texas Workforce Commission, a state agency that oversees workforce development programs, needed to overhaul its popular client/server application to keep up with growth in size and functionality. Using Sybase technology, it was able to re-architect and re-implement the application, reducing both the size and frequency of client releases.

Key Benefits

• Reduces size of the client by more than 75 percent
• Completed transition without added development costs
• Decreases number of database connections with transaction pooling

• Adaptive Server Enterprise
• EAServer
• PowerBuilder

• Public Sector

TWIST was originally developed as a two-tier client/server application with large PowerBuilder clients connecting directly to a Sybase database on the back end. TWIST has been a successful application with a growing number of government users and nearly 2.5 million people entered in its database. However, the rules governing the services were somewhat fluid and sensitive to regulatory changes.

In many ways, TWIST became a victim of its own success. As more business rules were added to the client-side application, not only did it grow in both size and functionality, but it became increasingly sensitive to changes in the laws and procedures represented by the business rules. Eventually, the TWC was facing a situation where they had 10,000 users of a 45-megabyte client application needing a patch release every three to four weeks in addition to major quarterly releases. This frequent synchronization of 10,000 clients was bogging down the FTP site used to deliver the releases.

The short cycle of patch releases was sapping productivity; frustrated users were often running back versions of the software or spending far too much time getting the latest TWIST client to their desktop.

PowerBuilder to EAServer: A Natural Extension
To fix the client-side release issues while retaining TWIST's core usability, TWC developed a multi-phase plan to move from a client/server version to a three-tier architecture built around an application server. TWC liked the PowerBuilder development environment and had a large library of existing PowerBuilder code. Their programming staff was comfortable and productive in PowerBuilder. Retooling their programming skills would have a negative effect on their ability to continue adding functionality to the system. Ideally, the selected application server would be able to leverage this existing investment in PowerBuilder talent and code.

After evaluating several application servers, TWC ultimately selected EAServer. Not only was EAServer a world-class application server capable of handling their current and future server needs, but EAServer had the additional, unique advantage of natively running PowerBuilder code.

Using EAServer to Thin the Client
Once the team got up to speed on EAServer, PowerBuilder non-visual objects (NVO), and three-tier architecture, they were ready to make some fundamental changes to the application, both in the database design and in the location of the business rules.

"TWIST was originally based on a case approach where caseworkers focused on state programs and everybody worked independently," said Chris Bohne, a lead contractor at TWC, who worked on TWIST. "TWC decided they wanted to become more customer-centric, where a caseworker can view an entire customer's history by just looking at the customer record. We completely redesigned the database; we wanted the capability to modify a person's record, not a case."

Bohne added, "The original system was designed around old state employment programs, which no longer existed. Over the years, new state programs were squeezed in by modifying the database a little bit here and there. For the newest release, we made the decision to align the database architecture with today's business model. We also took all the business rules that were on the client, moved them into non-visual objects, and did everything we could to thin out the client."

By moving the rules from the PowerBuilder client to EAServer, the team was able to trim the size of the client by more than 75 percent: from 45MB to 10MB. The reduction in the client size would dramatically lighten the load on the FTP site as new releases were downloaded. Even more important, the need to continually update the client with patch releases diminished because the business rules moved from the client to EAServer.

Injecting New Life into a Successful Application
By employing EAServer, the TWIST application was able to make the transition from its original client/server architecture to a three-tier architecture with a redesigned database. Without incurring the expenses of retooling the development staff or purchasing entirely new development environments, the transition was accomplished by augmenting the programmers' skill set and the existing code base. This approach revitalized a highly successful application by creating a new architecture that invites new users and easily supports additional functionality.

"We have been pleasantly surprised with the performance of EAServer on AIX," Bohne said. "We throw more users on the boxes and EAServer handles it well. We don't see a significant increase in the load as we add more users."