RDFStats - An Extensible RDF Statistics Generator and Library

In this paper RDFStats is introduced, which is a generator for statistics of RDF sources like SPARQL endpoints and RDF documents. RDFStats does not only provide a statistics generator, but also a powerful API for persisting and accessing statistics including several estimation functions that also support SPARQL filter-like expressions. For many Semantic Web applications like the Semantic Web Integrator and Query Engine (SemWIQ), which is currently developed at the University of Linz, detailed statistics about the contents of RDF data sources are very important. RDFStats has been primarily designed and implemented for the SemWIQ federator and optimizer, but it can also be used for other applications like linked data browsers, aggregators, or visualization tools. It is based on the popular Semantic Web framework Jena developed by HP Labs Bristol and can be easily extended and integrated into other applications.