Fast transaction commit

Abstract

A distributed computing system, having a sufficient number of devices and requiring a sufficiently large number of devices to select any proposal, can maintain synchronization between its constituent devices and respond to client requests with as few as two message delays. A leader can synchronize the devices of the system and establish a safe proposal number for all current and future steps of the system. Devices can then receive client requests directly, treating the request as a proposal having the proposal number determined previously by the leader, and voting for the proposal. If the client receives an indication from a least a quorum of devices, where a quorum can be the minimum number of devices that can be operational at a given time, the client can know that the request was selected. If two or more clients attempt to request different functions at approximately the same time, the system may not select either request, in which case a leader can be requested to determine if any requests may have been selected, and to reestablish a safe proposal number. Systems with fewer devices can also implement the message-delay-reducing algorithm if they can also revert to the standard Paxos algorithm if an insufficient number of devices are operational. Such algorithms can be used to provide an efficient method for determining whether to commit or abort a client transaction.