LSQ Framework: the LSQ Framework for SPARQL Query Log Processing.

The Linked SPARQL Queries (LSQ) datasets contain real-world SPARQL queries collected from the query logs of the publicly available SPARQL endpoints. In LSQ, each SPARQL query is represented as RDF with various structural and data-driven features attached. In this paper, we present the LSQ Java framework for creating rich knowledge graphs from SPARQL query logs. The framework is able to RDFize SPARQL query logs, which are available in different formats, in a scalable way. Furthermore, the framework offers a set of static and dynamic enrichers. Static enrichers derive information from the queries, such as their number of basic graph patterns and projected variables or even a full SPIN model. Dynamic enrichment involves additional resources. For instance, the benchmark enricher executes queries against a SPARQL endpoint and collects query execution times and result set sizes. This framework has already been used to convert query logs of 27 public SPARQL endpoints, representing 43.95 million executions of 11.56 million unique SPARQL queries. The LSQ queries have been used in many use cases such as benchmarking based on real-world SPARQL queries, SPARQL adoption, caching, query optimization, useability analysis, and meta-querying. Realization of LSQ required devising novel software components to (a) improve scalability of RDF data processing with the Apache Spark Big Data framework and (b) ease operations of complex RDF data models such as controlled skolemization. Following the spirit of OpenSource software development and the "don’t repeat yourself" (DRY) paradigm, the work on the LSQ framework also resulted in contributions to Apache Jena in order to make these improvements readily available outside of the LSQ context.