MESSAGE QUEUE MANAGEMENT SYSTEM, LOCK SERVER, MESSAGE QUEUE MANAGEMENT METHOD, AND MESSAGE QUEUE MANAGEMENT PROGRAM

PROBLEM TO BE SOLVED: To avoid a multi-master state due to network failure or server failure so as to improve performance of replication in a queue halfway state.SOLUTION: The present invention uses Paxos as a majority protocol for assuring the constant presence of one master to determine whether or not the own device is a master and if the master is replaced, confirms an effective session by means of queue information replicated previously in a database storing a queue and information of the queue and a reconnection request from a client, replicates a halfway state of operation to the queue, and if the master is not replaced, replicates data. By marking or unmarking (setting/resetting of session ID for key) to the queue in the database as a queue operation, the halfway state is assured.