Replication is a widely used method for achieving high availability in database systems. Due to the nondeterminism inherent in traditional concurrency control schemes, however, special care must be taken to ensure that replicas don’t
diverge. Log shipping, eager commit protocols, and lazy synchronization protocols are well-understood methods for
safely replicating databases, but each comes with its own cost in availability, performance, or consistency.
In this paper, we propose a distributed database system which combines a simple deadlock avoidance technique with