Architectures and monitoring techniques for active databases: An evaluation

摘要

The need for active capability for non-traditional applications and its concomitant benefits are well-established. Although the event-based technique for monitoring conditions (leading to the integrated architecture) is the most versatile of all the techniques, from a practical viewpoint there is a need for enhancing pre-existing non-active DBMSs to support active capability. The set of techniques that can be used for providing this add-on active capability (leading to the layered architecture) imposes certain limitations on the extent of active capability that can be supported. Insights into the details of techniques as well as their impact on the architecture entails a design that better meets the active database objectives.This paper identifies a repertoire of techniques for condition monitoring and discusses their suitability to different architectures. This paper argues that from a pragmatic viewpoint, both layerd and Integrated approaches to support active capability need to be pursued. Then it comes polling and event-based or asynchronous monitoring techniques using an implementation on Symbolics using Common Lisp with Flavors. The focus of this comparison is on: techniques, performance, influence of implementation strategies on performance, and identification of opportunities for optimization.