Distributed Events in Sentinel: Design and Implementation of a Global Event Detector

Abstract

Abstract : In conventional database management systems, data are created, updated, retrieved and deleted in a passive way; that is, only in response to operations performed by users or application programs. Active database management systems (ADBMSs) enhance the functionality of conventional database systems by issuing operations on their own in response to event occurrences or satisfied conditions. ECA (event-condition-action) rules are used to capture this activity capability: when an event is detected, a condition is checked and an action is executed if the condition is satisfied. Many computing applications are distributed in nature and hence require support for distributed computing. Many of the active OODBMS developed recently do not address event specification outside of their address space. Rules cannot be specified on events that occur in one or more applications. That is, none of them addresses processing ECA rules in a distributed environment. This report extends the earlier work on Sentinel and APBMS, by supporting global event specification and detection. Global events definitions are extended to Snoop, and a global event detector (GED) is implemented to detect events that span multiple applications.