We present Owlgres, a DL-Lite reasoner implementation written for PostgreSQL, a mature open source database. Owlgres is an OWL reasoner that provides consistency checking and conjunctive query services, supports DL-LiteR as well as the OWL sameAs construct, and is not limited to PostgreSQL. We discuss the implementation with special focus on sameAs and the supported subset of the SPARQL language. Emphasis is given to the implemented optimization techniques which resulted in significant performance improvement. Based on a confidential NASA dataset and part of the DBpedia dataset, we show a typical use case for Owlgres, i.e. given a terminology and a dataset, Owlgres provides querying on a persistent knowledge base with reasoning at query time in the expressivity of DL-LiteR.