The emergence computation of overflow in dynamic XML tree based on prefix and interval labelling schemes

Abstract

Despite the fact that dynamic XML labelling schemes have been investigated widely, some challenges still need to be tackled. Dynamic XML documents are subject to change. An efficient dynamic labelling scheme is able to maintain the node relationships throughout continuous changes to the XML tree structure. Such a scheme generates labels for new nodes to avoid the need to relabel the whole tree. The main problem for dynamic XML is overflow that occurs when the label's length of the new node is over the reserved space limit. There has not been sufficient analysis to determine the class of labelling scheme which faces this problem in the early stages of update. To this end a series of experiments were performed when updating the Nasa XML database, which contains real data. Five sets of new nodes (50, 100, 400, 800, 1200) were inserted into this dataset using two versions of XML node indexing system: a Prefix and an Interval labelling scheme. It was found that Interval falls victim to the problem of overflow after the insertion of only 100 nodes whereas Prefix has no problem even when adding 1200 nodes.