The Concurrency Control Mechanism of SDD-1: A System for Distributed Databases (The Fully Redundant Case)

SDD-1, A System for Distributed Databases, is a distributed database system being developed by Computer Corporation of America (CCA), Cambridge, MA. SDD-1 permits data to be stored redundantly at several database sites in order to enhance the reliability and responsiveness of the system and to facilitate upward scaling of system capacity. This paper describes the method used by SDD-1 for updating data that are stored redundantly.