Using Datacycle for Concurrency Control in a Distributed Database Environment

This study proposes DC-ROLL, a new approach to concurrency control in a distributed environment based on the Request Order Linked List (ROLL) [P91] and the Datacycle architecture [H+87]. DC-ROLL allows for more flexibility in levels of concurrency and avoids certain performance bottlenecks of the traditional two-phase locking. Unlike the original Datacycle architecture where the entire database along with concurrency control structures is pumped to access managers (sites), the DC-ROLL architecture only requires broadcasting the ROLL, the database concurrency control object. As a result, DC-ROLL has much lower network bandwidth requirements. DC-ROLL eliminates the burden of concurrency control from the sites storing the data being accessed. Instead, all concurrency control functions are handled at the sites where transactions run. DC-ROLL also simplifies database consistency management in replicated environments since no centralized (primary) concurrency control manager is needed.