Node labeling schemes for dynamic XML documents reconsidered

We explore suitable node labeling schemes used in collaborative XML DBMSs (XDBMSs, for short) supporting typical XML document processing interfaces. Such schemes have to provide holistic support for essential XDBMS processing steps for declarative as well as navigational query processing and, with the same importance, lock management. In this paper, we evaluate existing range-based and prefix-based labeling schemes, before we propose our own scheme based on DeweyIDs. We experimentally explore its suitability as a general and immutable node labeling mechanism, stress its synergetic potential for query processing and locking, and show how it can be implemented efficiently. Various compression and optimization measures deliver surprising space reductions, frequently reduce the size of storage representation—compared to an already space-efficient encoding scheme—to less than 20–30% in the average and, thus, conclude their practical relevance.