A Registration protocol is used in transaction processing for normal operations. If an error occurs, the system reverts to a Full Broadcast protocol. The Registration Protocol reduces the number of messages that are sent among CPUs in a cluster thereby permitting performance improvements in the system. The Registration Protocol has Begin, DP2 Check, Phase 1 Flush and Phase 2 (lock release) phases just as does the Full Broadcast Protocol, thereby permitting the Full Broadcast protocol to step in at any phase after an error is detected.