Stars on Steroids: Fast Evaluation of Multi-source Star Twig Queries in RDBMS

  • Erwin Leonardi
  • Sourav S. Bhowmick
  • Fengrong Li
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7238)


Despite a large body of work on xml twig query processing in relational environment, systematic study of xml join evaluation has received little attention in the literature. In this paper, we propose a novel and non-traditional technique for fast evaluation of multi-source star twig queries in a path materialization-based rdbms. A multi-source star twig joins different xml documents on values in their nodes and the XQuery graph takes a star-shaped structure. Such queries are prevalent in several domains such as life sciences. Rather than following the conventional approach of generating one huge complex sql query from a twig query, we translate a star query into a list of sql sub-queries that only materializes minimal information of underlying xml subtrees as intermediate results. Experiments carried out confirm that our proposed approach build on top of an off-the-shelf commercial rdbms has excellent real-world performance.


Query Evaluation Output Expression Twig Pattern Twig Query XQuery Query 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    W3C. XQuery 1.0 Grammar Test Page (2005),
  2. 2.
    Boncz, P., Grust, T., et al.: MonetDB/XQuery: A Fast XQuery Processor Powered by a Relational Engine. In: SIGMOD (2006)Google Scholar
  3. 3.
    Brantner, M., Kanne, C.-C., Moerkotte, G.: Let a Single FLWOR Bloom (to improve XQuery plan generation). In: XSym Workshop (2007)Google Scholar
  4. 4.
    Deutsch, A., Tannen, V.: MARS: A System for Publishing xml from Mixed and Redundant Storage. In: VLDB (2003)Google Scholar
  5. 5.
    Fernandez, M., Morishima, A., Suciu, D.: Efficient Evaluation of xml Middle-ware Queries. In: SIGMOD (2001)Google Scholar
  6. 6.
    Gou, G., Chirkova, R.: Efficiently Querying Large xml Data Repositories: A Survey. IEEE TKDE 19(10) (2007)Google Scholar
  7. 7.
    Grust, T., Rittinger, J., Teubner, J.: Why Off-the-Shelf RDBMSs are Better at XPath Than You Might Expect. In: SIGMOD (2007)Google Scholar
  8. 8.
    Grust, T., Sakr, S., Teubner, J.: XQuery on SQL Hosts. In: VLDB (2004)Google Scholar
  9. 9.
    Krishnamurthy, R., Kaushik, R., Naughton, J.F.: Efficient xml-to-sql Query Translation Literature: State of the Art and Open Problems. In: XSym (2003)Google Scholar
  10. 10.
    Leonardi, E., Bhowmick, S.S., Li, F.: Fast Evaluation of Multi-source Star Twig Queries in a Path Materialization-based xml Database. Technical Report (2010),
  11. 11.
    Manolescu, I., Florescu, D., Kossmann, D.: Answering xml Queries over Heterogeneous Data Sources. In: VLDB (2001)Google Scholar
  12. 12.
    O’Neal, P., O’Neal, E., Pal, S., et al.: ORDPATHs: Insert-Friendly xml Node Labels. In: SIGMOD (2004)Google Scholar
  13. 13.
    Pal, S., Cseri, I., Seeliger, O., et al.: XQuery Implementation in a Relational Database System. In: VLDB (2005)Google Scholar
  14. 14.
    Seah, B.-S., Widjanarko, K.G., Bhowmick, S.S., Choi, B., Leonardi, E.: Efficient Support for Ordered XPath Processing in Tree-Unaware Commercial Relational Databases. In: Kotagiri, R., Radha Krishna, P., Mohania, M., Nantajeewarawat, E. (eds.) DASFAA 2007. LNCS, vol. 4443, pp. 793–806. Springer, Heidelberg (2007)CrossRefGoogle Scholar
  15. 15.
    Shanmugasundaram, J., Tufte, K., et al.: Relational Databases for Querying xml Documents: Limitations and Opportunities. In: VLDB (1999)Google Scholar
  16. 16.
    Shanmugasundaram, J., Kiernan, J., et al.: Querying xml Views of Relational Data. In: VLDB (2001)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Erwin Leonardi
    • 1
    • 2
  • Sourav S. Bhowmick
    • 1
    • 2
  • Fengrong Li
    • 3
  1. 1.Singapore-MIT AllianceNanyang Technological UniversitySingapore
  2. 2.School of Computer EngineeringNanyang Technological UniversitySingapore
  3. 3.Japan Advanced Institute of Science and TechnologyJapan

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