Using dummy reads to maintain consistency in heterogeneous database systems

A distributed heterogeneous database system is a collection of interconnected local database systems with diverse properties and local autonomy. In such a system, it is difficult to maintain consistency without compromising local autonomy. A global concurrency control protocol is proposed that maintains consistency without compromising local autonomy. The scheme is based on the observation that sufficient read operations attached to global transactions can prevent local schedules from diverging while keeping the database states intact. The protocol is simple and easy to implement. It does not require the knowledge about local concurrency control methods. Thus local concurrency control mechanisms can be changed without affecting the global concurrency control scheme