Making an object-oriented DBMS active: Design, implementation, and evaluation of a prototype

Abstract

Extant databases are passive in nature and offer little or no support for automatically monitoring conditions defined over the state of the database. In fact such a capability is central for a variety of applications requiring timely and time-constrained data management and processing (e.g., cooperative processing, process control, air traffic control, threat analysis).

Traditionally, the effect of condition monitoring has been realized either by encoding condition evaluation as part of the application program or by polling the database (periodically) for condition evaluation. This paper explores a third alternative, viz. active condition monitoring from an object-oriented design perspective. The focus of this paper is on the design and implementation of active condition monitoring functionality for an object-oriented Database Management System (DBMS) and its evaluation: performance comparison with polling, influence of implementation strategies on performance, and identification of opportunities for optimization.

This work was carried out when the authors were with Xerox Advanced Information Technology (previously Advanced Information Technology Division of Computer Corporation of America), 4 Cambridge Center, Cambridge, MA 02142. This work was supported by the Defense Advanced Research Projects Agency and by Rome Air Development Center under contract No. F30602-87-C-0029. The views and conclusions contained in this paper are those of the authors and do not necessarily represent the official policies of the Defense Advanced Research Projects Agency, the Rome Air Development Center, or the U.S. Government.