Patent attributes
Each replica in a group of replicas of a data set is assigned a unique identifier and maintains an independent counter. When a change is made to an element in the data set, a change bucket, is assigned to the changed data element. The change bucket includes the identifier of the replica at which the change was made and the count of the counter of the replica at which the change was made at the time of the change. Each replica also maintains an array of change buckets each corresponding to the most recent changes replicated from the other replicas in the group. When replicas synchronize, the replicas exchange and compare replication state vectors to identify changes present at a replica and not present at another replica. Once such changes are identified, they and their corresponding change buckets are sent to the other replica to be replicated. Once new changes are replicated, the replicas join their replication state vectors to reflect that they are synchronized.
