KF-Diff+: Highly Efficient Change Detection Algorithm for XML Documents

Most previous work in change detection on XML documents used the ordered tree, with the best complexity of O(nlogn), where n is the size of the document. The best algorithm we had ever known for unordered model achieves polynomial time in complexity. In this paper, we propose a highly efficient algorithm named KF-Diff+. The key property of our algorithm is that the algorithm transforms the traditional tree-to-tree correction into the comparing of the key trees which are substantially label trees without duplicate paths with the complexity of O(n), where n is the number of nodes in the trees. In addition, KF-Diff+ is tailored to both ordered trees and unordered trees. Experiment shows that KF-Diff+ can handle XML documents at extreme speed.