Patent attributes
A method and apparatus to generate information representing differences between two data sets are described. Information representing differences between a first data set and a second data set is acquired, where the first and second data sets each include multiple nodes. A traversal map that identifies nodes for which a difference has been detected between the first and second data sets is generated, and then during an output phase, a hierarchy of nodes is traversed to generate output indicating user-level differences between the first and second data sets. The traversal map is used to avoid traversing at least some of the nodes in the hierarchy during the output phase. A child map may be generated to represent parent-child relationships between the nodes and used during the output phase to prefetch certain nodes in the hierarchy.