Reducing the Cost for Non-Blocking in Atomic Commitment

Non-blocking atomic commitment protocols enable a decision (commit or abort) to be reached at every correct participant, despite the failure of others. The cost for non-blocking implies however (1) a high number of messages and communication steps required to reach commit, and (2) a complicated termination protocol needed in the case of failure suspicions. In this paper, we present a non-blocking protocol, called MD3PC (Modular and Decentralized Three Phase Commit), which enables to trade resiliency against eeciency. As conveyed by our performance measures, MD3PC is faster than existing non-blocking protocols, and in the case of a broadcast network and a reasonable resiliency rate (e.g 2 or 3) is almost as eecient as the classical (blocking) 2PC. The termination protocol of MD3PC is encapsulated inside a majority consensus protocol. This modularity leads to a simple structure of MD3PC and enables a precise characterization of its liveness in an asynchronous system with an unreliable failure detector.