Concurrency control for object bases

摘要

This paper presents concurrency control techniques suitable for engineering design environments. Design environments are quite different from conventional business applications for which databases have been traditionally used. Transactions in a design application are usually very long compared with those in traditional applications, necessitating new concurrency control techniques. We present the Dynamic Validation concurrency control scheme, an optimistic concurrency control scheme that avoids locking data items for extended periods of time. Dynamic validation is designed specifically for low-contention object-oriented database applications with long-duration transactions, such as engineering design applications. We prove that dynamic validation enforces executions that are “serializable with respect to the database state”. This correctness criterion relaxes the classical serializability criterion, and allows schedules that are equivalent, i.e. produce the same effect, to a serial execution of transactions starting from the same initial database state.