Relational DBs rev up for high-end TP - transaction processing in client/server environments tests the limits of relational technology - includes a related article on whether the two-tier client/server architecture is sufficient for large-scale online transaction processing

Software Magazine, Oct, 1995 by Barbara Francett

Now, as the company's need for highly distributed systems increases, Maring has another concern. "Most transaction managers assume a syhchronized two-phase commit and rollback; that is, all locks hold globally for a unit of work. When systems are highly distributed, that's a problem, because the lock time kills transaction rates. A global transaction needs to use a queued asynchronous model with transaction integrity that guarantees delivery without locks. That doesn't exist today, and it is desperately needed."

Still, some help is on the way that will give users more flexibility and transparency in their development of two- and three-tier applications.

One solution comes from Open Horizon, Belmont, Calif. The company offers Connection, a modular software product for two-tier environments that replaces the native database connection mechanism with DCE remote procedure call (RPC) connection services, providing transparent access to diverse databases and TP monitors, as well as to authentication, encryption and directory services. A version that supports distributed three-tier environments is forthcoming in the next few months, according to the company.

The distributed computing services group at Deloitte & Touche, Los Angeles, has been using Connection for almost a year, according to John Dohm, manager, and Scott Kandel, senior manager. "Over the long haul, certain applications lend themselves to two-tier, others to three-tier," said Dohm. "We'll need to mix and match."

For developers, the product provides a smooth migration from two-tier to three-tier applications, the managers said. "One connection `widget' on the workstation will provide transparent access to both two- and three-tier environments," Kandel said. "The key item," added Dohm, "is that we'll be able to design applications contingent on our needs."