On the Selection of SPARQL Endpoints to Efficiently Execute Federated SPARQL Queries

  • Maria-Esther VidalEmail author
  • Simón Castillo
  • Maribel Acosta
  • Gabriela Montoya
  • Guillermo Palma
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9620)


We consider the problem of source selection and query decomposition in federations of SPARQL endpoints, where query decompositions of a SPARQL query should reduce execution time and maximize answer completeness. This problem is in general intractable, and performance and answer completeness of SPARQL queries can be considerably affected when the number of SPARQL endpoints in a federation increases. We devise a formalization of this problem as the Vertex Coloring Problem and propose an approximate algorithm named Fed-DSATUR. We rely on existing results from graph theory to characterize the family of SPARQL queries for which Fed-DSATUR can produce optimal decompositions in polynomial time on the size of the query, i.e., on the number of SPARQL triple patterns in the query. Fed-DSATUR scales up much better to SPARQL queries with a large number of triple patterns, and may exhibit significant improvements in performance while answer completeness remains close to 100 %. More importantly, we put our results in perspective, and provide evidence of SPARQL queries that are hard to decompose and constitute new challenges for data management.


SPARQL Query Query Plan Source Selection Triple Pattern Query Engine 
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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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Maria-Esther Vidal
    • 1
    Email author
  • Simón Castillo
    • 1
  • Maribel Acosta
    • 2
  • Gabriela Montoya
    • 3
  • Guillermo Palma
    • 1
  1. 1.Universidad Simón BolívarCaracasVenezuela
  2. 2.Institute AIFBKarlsruhe Institute of TechnologyKarlsruheGermany
  3. 3.University of NantesNantesFrance

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