Patent ID: 8478790

Claim:
A database management system comprising: a network interface, for receiving database queries from two or more client application processes as a network database service, the client application processes originating from two different users, the system providing a least one connection into the system for each such client application process; a group of two or more operational nodes for executing the queries as database operations, each operational node implemented as a logical collection of software components that execute on one or more physical machines; where the number of physical machines is not necessarily the same as the number of operational nodes; with one or more of the operational nodes assigned as storage-nodes, and groups of storage-nodes forming storage nodegroups; the number of operational nodes assigned as storage-nodes varying during execution of the queries; the queries also specifying one or more tables for an associated database operation, with each such table being assigned to a respective storage nodegroup the system further: distributing data from the tables among the nodes in a storage nodegroup according to a data dependent distribution method specified by a Distribution Vector (DV), the DV based on a set of attributes of the table that determine at least where each row is stored; and associating with each storage nodegroup one or more generations, such that when a storage nodegroup is initially created it has a first generation, and such that the generation consists of at least a generation number, a Distribution Map (DM), and an Allocation Strategy (AS); and further wherein information recorded for a given generation is recorded in a format different from a format used to record information associated with another generation.