On the Use of a Reflective Architecture to Augment Database Management Systems

Abstract: The Database Management System (DBMS) used to be a commodity soft- ware component, with well known standard interfaces and semantics. However, the performance and reliability expectations being placed on DBMSs have increased the demand for a variety add-ons, that augment the functionality of the database in a wide range of deployment scenarios, offering support for features such as clustering, replica- tion, and self-management, among others. A well known software engineering approach to systems with such requirements is reflection. Unfortunately, standard reflective in- terfaces in DBMSs are very limited. Some of these limitations may be circumvented by implementing reflective features as a wrapper to the DBMS server. Unfortunately, these solutions comes at the expense of a large development effort and significant per- formance penalty. In this paper we propose a general purpose DBMS reflection architecture and interface, that supports multiple extensions while, at the same time, admitting efficient imple- mentations. We illustrate the usefulness of our proposal with concrete examples, and evaluate its cost and performance under different implementation strategies.