Processing transactions over optimistic atomic broadcast protocols

Atomic broadcast primitives allow fault-tolerant cooperation between sites in a distributed system. Unfortunately, the delay incurred before a message can be delivered makes it difficult to implement high performance, scalable applications on top of atomic broadcast primitives. A new approach has been proposed which, based on optimistic assumptions about the communication system, reduces the average delay for message delivery. We develop this idea further and present a replicated database architecture that employs the new atomic broadcast primitive in such a way that the coordination phase of the atomic broadcast is fully overlapped with the execution of transactions, providing high performance without relaxing transaction correctness.