Incremental Maintenance of 2-Hop Labeling of Large Graphs

• Published in: IEEE transactions on knowledge and data engineering Vol. 22; no. 5; pp. 682 - 698
• Main Authors: Bramandia, R., Choi, B., Wee Keong Ng
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2010; IEEE Computer Society; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Artificial intelligence; Collection; Computer science; control theory; systems; Computer Society; Computer systems and distributed systems. User interface; Database languages; Exact sciences and technology; Extensible Markup Language; Graphs; Indexing; Indexing methods; Information retrieval. Graph; Information systems. Data bases; Labeling; Maintenance; Marking; Memory organisation. Data processing; Ontologies; OWL; query processing; Resource description framework; Semantic Web; Semantics; Software; Speech and sound recognition and synthesis. Linguistics; Studies; Testing; Theoretical computing; XML; XML/XSL/RDF; Database query; Ontology; Metadata; XML language; Updating; Graph theory; Maintenance; Reachability; Semantic web; Query processing; Graph connectivity; XML/XSL/RDF; News; World wide web; Database; Set covering; Indexing methods; Internet; Graph labelling; Indexing
• ISSN: 1041-4347; 1558-2191
• DOI: 10.1109/TKDE.2009.117

Recent interests on XML, the Semantic Web, and Web ontology, among other topics, have sparked a renewed interest on graph-structured databases. A fundamental query on graphs is the reachability test of nodes. Recently, 2-hop labeling has been proposed to index a large collection of XML and/or graphs for efficient reachability tests. However, there has been few work on updates of 2-hop labeling. This is compounded by the fact that data may often change over time. In response to these, this paper studies incremental maintenance of 2-hop labeling. We identify the main reason for the inefficiency of updates of existing 2-hop labels. We propose three updatable 2-hop labelings, hybrids of 2-hop labeling, and their incremental maintenance algorithms. The proposed 2-hop labeling is derived from graph connectivity, as opposed to set cover which is used by most previous works. Our experimental evaluation illustrates the space efficiency and update performance of various kinds of 2-hop labelings. Our results show that our incremental maintenance algorithm can be two orders of magnitude faster than previous methods and the size of our 2-hop labeling can be comparable to existing 2-hop labeling. We conclude that there is a natural way to spare some index size for update performance in 2-hop labeling.