Database system, computer program product, and data processing method

Abstract

According to an embodiment, a database system includes a plurality of nodes in which a database is stored; and a management device configured to manage the plurality of nodes. The management device includes a first assigning unit and a second assigning unit. Depending on a change in state of each of the plurality of nodes, the first assigning unit assigns a first node, which stores therein data pieces and receives an access request with respect to the data pieces, and assign a second node, which stores therein the data pieces and serves as a backup node for the first node, and instructs each of the plurality of nodes to perform operations according to assignment. Depending on a state of the plurality of nodes and depending on a change in assignment state of the first node and the second node, the second assigning unit assigns a third node which is a candidate node to serve as the first node or the second node, and instructs each of the plurality of nodes to make preparation for causing the third node to operate as the first node or the second node. Each of the plurality of nodes includes a transferring unit configured to send the data pieces of the first node or the second node to the third node.