Strategies for executing federated queries in SPARQL1.1

Date: September 17, 2014

Speaker: Carlos Buil Aranda

Abstract

Currently there are hundreds of SPARQL endpoints on the Web exposing the RDF data stored in their database systems. However, servers hosting SPARQL endpoints often restrict access to these data by limiting the amount of results returned per query or the amount of queries per time that a client may issue. As this may affect query completeness when using SPARQL1.1’s Federated Query extension, we analysed different strategies to implement federated queries with the goal to circumvent endpoint limits. In this talk and using a Bio2RDF use case, we present several methods for decomposing SPARQL federated queries and show that some of these methods provide unsound results in the general case. We will provide fixes to these problems and we will discuss under which restrictions these recipes are still applicable. Finally, we will present an evaluation of the proposed strategies for checking their feasibility in practice.

References

• Carlos Buil-Aranda, Axel Polleres, and Jürgen Umbrich. Strategies for executing federated queries in SPARQL1.1. In Proceedings of the 13th International Semantic Web Conference (ISWC 2014), Lecture Notes in Computer Science (LNCS). Springer, October 2014 (see pdf at the bottom of the page)

Bio

Carlos Buil-Aranda is a postdoctoral researcher at the Department of Computer Science, Pontificia Universidad Católica de Chile (funded by Fondecyt grant 3130617). He received his PhD from Universidad Politécnica de Madrid in February 2012. He then moved to Chile and currently works at the Datalab Research Group researching on the Semantic Web. He focus in SPARQL Federated Query Processing, and trying to improve the SPARQL user queries by analysing the endpoint’s query logs. He has several papers in international conferences and journals and was also awarded with the Best Research Paper Award at the Extended Semantic Web Conference 2011 and the Best Evaluation Paper Award at the International Semantic Web Conference 2013. He was editor of the W3C SPARQL 1.1 Federation Extension recommendation and he also participated in other international standardisation organisms as well as in several international research projects.