Formalization of Recovery

Abstract

Database recovery guarantees the consistency of the database in the event of transaction, system, and media failure, any of which may happen for a variety of reasons. Robust recovery is, therefore, an essential feature of any DBMS. However, in spite of its important role in the functionality of DBMS and vast experience in building recovery systems, the process of recovery has not been treated on a conceptual level. A careful review of the literature on recovery reveals that there is a semantic gap between high level requirements such as the all-or-nothing property, and recoverability and how these requirements are implemented, in terms of buffers and their policies, volatile and persistent storage, shadowing, etc. The advent of new transaction models for dealing with nontraditional applications makes the recovery even more important, and, therefore, elevating recovery from a process to a concept is desirable.

Article FootNote

This chapter is entirely based on the paper written by by Cris Pedregal Martin, Arvind Nithrakashyap, Krithi Ramamritham, and Jay Shanmugasundaram. All original figures have been redrawn and the article has been reformatted for this book. A version of the original article also appeared in S. Jajodia and L. Kerschberg, eds., Advanced Transaction Models and Architectures, Kluwer Academic Publishers, Boston, 1997.