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Decomposing Federated Queries in Presence of Replicated Fragments

23 Pages Posted: 24 Jun 2018 First Look: Accepted

See all articles by Gabriela Montoya

Gabriela Montoya

University of Nantes - Laboratoire d’Informatique (LINA)

Hala Skaf-Molli

University of Nantes - Laboratoire d’Informatique (LINA)

Pascal Molli

University of Nantes - Laboratoire d’Informatique (LINA)

Maria-Esther Vidal

Universidad Simón Bolívar (USB) - Computer Science Department

Abstract

Federated query engines allow for linked data consumption using SPARQL endpoints. Replicating data fragments from different sources enables data re-organization and provides the basis for more effective and efficient federated query processing. However, existing federated query engines are not designed to support replication. In this paper, we propose a replication-aware framework named LILAC, sparqL query decomposItion against federations of repLicAted data sourCes, that relies on replicated fragment descriptions to accurately identify sources that provide replicated data. We dened the query decomposition problem with fragment replication (QDP-FR). QDP-FR corresponds to the problem of finding the sub-queries to be sent to the endpoints that allows the federated query engine to compute the query answer, while the number of tuples to be transferred from endpoints to the federated query engine is minimized. An approximation of QDP-FR is implemented by the LILAC replication-aware query decomposition algorithm. Further, LILAC techniques have been included in the state-of-the-art federated query engines FedX and ANAPSID to evaluate the benefits of the proposed source selection and query decomposition techniques in different engines. Experimental results suggest that LILAC efficiently.

Keywords: Linked Data, Federated Query Processing, Query Decomposition, Fragment Replication

Suggested Citation

Montoya, Gabriela and Skaf-Molli, Hala and Molli, Pascal and Vidal, Maria-Esther, Decomposing Federated Queries in Presence of Replicated Fragments (2017). Journal of Web Semantics First Look. Available at SSRN: https://ssrn.com/abstract=3199272 or http://dx.doi.org/10.2139/ssrn.3199272

Gabriela Montoya (Contact Author)

University of Nantes - Laboratoire d’Informatique (LINA) ( email )

2, rue de la Houssinière
Nantes
France

Hala Skaf-Molli

University of Nantes - Laboratoire d’Informatique (LINA) ( email )

2, rue de la Houssinière
Nantes
France

Pascal Molli

University of Nantes - Laboratoire d’Informatique (LINA) ( email )

2, rue de la Houssinière
Nantes
France

Maria-Esther Vidal

Universidad Simón Bolívar (USB) - Computer Science Department ( email )

Sartenejas
Caracas
Venezuela

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