An empirical study of real-world SPARQL queries

Understanding how users tailor their SPARQL queries is cru-cial when designing query evaluation engines or fine-tuning RDF stores with performance in mind. In this paper we an-alyze 3 million real-world SPARQL queries extracted from logs of the DBPedia and SWDF public endpoints. We aim at finding which are the most used language elements both from syntactical and structural perspectives, paying special attention to triple patterns and joins, since they are indeed some of the most expensive SPARQL operations at evalu-ation phase. We have determined that most of the queries are simple and include few triple patterns and joins, be-ing Subject-Subject, Subject-Object and Object-Object the most common join types. The graph patterns are usually star-shaped and despite triple pattern chains exist, they are generally short