Patent ID: 8832113

Claim:
A data management apparatus operable in a distributed management system to distributively manage data, comprising: a first storage configured to store key information in which a hash value that is obtained by applying a predetermined hash function to the key information belongs to a first range of a hash space, and data corresponding to the key information, in a related manner; a second storage configured to store identification information of another data management apparatus within the distributed management system in correspondence with a certain range of the hash space, when executing a changing process, so that the identification information of each data management apparatus within the distributed management system is stored in the second storage for each range of the hash space; and a processing unit configured to execute a process including first sending specific data included in the data stored in the first storage and key information corresponding to the specific data to the other data management apparatus, when executing the changing process to change a storage destination of the specific data in which a hash value that is obtained by applying the predetermined hash function to corresponding key information belongs to the certain range, from the data management apparatus to the other data management apparatus; and second sending the identification information of the other data management apparatus stored in correspondence with the certain range to a request source of an operation request, when the operation request with respect to data corresponding to first key information is received after the changing process and a hash value that is obtained by applying the predetermined hash function to the first key information belongs to the certain range, wherein a number of ranges into which the hash space is segmented is greater than a total number of data management apparatuses, including the data management apparatus and the other data management apparatus, provided within the distributed management system, and wherein the changing process changes a covering range of the data management apparatus in order to change a data arrangement that is biased to at least one range within the covering range.