Title: Evaluation of some optimisation techniques for semantic query answering on shared-nothing architecture

Authors: Tomasz Wiktor Wlodarczyk; Han Yi; Xiao Yu; Chunming Rong

Addresses: Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway. ' Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway. ' Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway. ' Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway

Abstract: In this paper, we present an evaluation of several optimisation techniques for semantic query answering for large datasets. We investigate influence of cluster configuration parameters on performance of different types of queries. We also compare data materialisation against query rewriting demonstrating that for more complex queries performance of query rewriting is not satisfactory. We also test performance of different types of encoding demonstrating that integer encoding can significantly improve the performance, but it is sensitive to implementation of its internal methods.

Keywords: semantic queries; querying; optimisation; Hadoop; SPARQL; Cascalog; encoding; data materialisation; query rewriting; query answering; cluster configuration.

DOI: 10.1504/IJSSC.2012.045567

International Journal of Space-Based and Situated Computing, 2012 Vol.2 No.1, pp.12 - 22

Received: 16 Jul 2011
Accepted: 21 Nov 2011
Published online: 20 Sep 2014 *

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