RWTH Aachen University
When providing public access to data on the semantic Web, publishers have various options that include downloadable dumps, Web APIs, and SPARQL endpoints. Each of these methods is most suitable for particular scenarios. SPARQL provides the richest access capabilities and is the most suitable option when granular access to the data is needed. However, SPARQL expressivity comes at the expense of high evaluation cost. The potentially large variance in the cost of different SPARQL queries makes guaranteeing consistently good quality of service a very difficult task.