Efficient Processing of XML Path Queries Using the Disk-based F&B Index

With the proliferation of XML data and applications on the Internet, efficient XML query processing techniques are in great demand. Answering queries using XML indexes is a natural approach. A number of XML indexes have been proposed in the literature; among them, F&B Index is one powerful index as it is the smallest index that answers all twig queries. However, an F&B Index suffers from the following two problems: (1) it was originally proposed as a memory-based index while its size is usually large in practice and (2) answering queries using an F&B Index is not fully optimized. These problems limit the benefits and even applications of F&B Indexes in practice. In this paper, we propose a highly optimized disk organization method for an F&B Index; the result is a disk-based F&B Index with good clustering properties. In addition, novel query processing algorithms exploiting the physical organization of the disk-based F&B Indexes are proposed. Experimental results verify that our disk-based F&B Index can scale up for large data size with good query performance compared with state-ofthe-art XML query processing algorithms. ∗This work was partially supported by UNSW FPG Grant (PS06863), UNSW Goldstar Grant (PS07248), and ARC Discovery Grant (DP0346004). Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Very Large Data Base Endowment. To copy otherwise, or to republish, requires a fee and/or special permission from the Endowment. Proceedings of the 31st VLDB Conference, Trondheim, Norway, 2005