Implementation of commit timestamps in Avalon

Atomic transactions have become a widely accepted mechanism for coping with failures and concurrency in reliable distributed systems. Much recent work has focused on concurrency control algorithms, in particular on techniques for exploiting type-specific properties of data objects to enhance concurrency. One class of concurrency control algorithms that appears particularly promising are "hybrid" schemes in which transactions are assigned timestamps as they commit. Although these algorithms have received extensive theoretical analysis, they have not been implemented because they require non-trivial systems support. In this paper, we describe the first implementation of transaction commit timestamps, as provided in Avalon/C++, a high-level language for reliable distributed computing. We focus on the run-time data structures and algorithms needed to achieve a practical implementation of transaction commit timestamps. This research was sponsored by the Avionics Lab, Wright Research and Development Center, Aeronautical Systems Division (AFSC), U. S. Air Force, Wright-Patterson AFB, OH 45433-6543 under Contract F33615-90-C-1465, Arpa Order No. 7597. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the U.S. Government.