Federated SPARQL Query Processing over Heterogeneous Linked Data Fragments

Abstract

Linked Data Fragments (LDFs) are Web interfaces that enable querying knowledge graphs on the Web. These interfaces, such as SPARQL endpoints or Triple Pattern Fragment servers, differ in the SPARQL expressions they can evaluate and the metadata they provide. So far, federated query processing has focused on federations with a single type of LDF interface, typically SPARQL endpoints. In this work, we address the challenges of SPARQL query processing over federations with heterogeneous LDF interfaces. To this end, we propose an interface-aware framework and illustrate its applicability with a prototypical approach. The results over the FedBench benchmark show a substantial improvement in performance by devising this interface-aware approach that exploits the capabilities of heterogeneous interfaces in federations.