Modular Concurrency Control and Failure Recovery

This paper presents an approach to concurrency control based on the decomposition of both the database and the individual transactions. This approach is a generalization of serializability theory in that the set of permissible transaction schedules contains all the serializable schedules. In addition to providing a higher degree of concurrency than that provided by serializability theory, this approach retains three important properties associated with serializability: the consistency of the database is preserved, the individual transactions are executed correctly, and the concurrency control approach is modular, a concept formalized in this paper. The associated failure recovery procedure is also presented as is the concept of failure safety.