[refset]

RDFox offers a rather impressive sounding Datalog inferencing engine: https://www.oxfordsemantic.tech/rdfox

> We present a novel approach to parallel materialisation (i.e., fixpoint computation) of datalog programs in centralised, main-memory, multi-core RDF systems. Our approach comprises an algorithm that evenly distributes the workload to cores, and an RDF indexing data structure that supports efficient, ‘mostly’ lock-free parallel updates.

> Materialisation is PTIME-complete in data complexity and is thus believed to be inherently sequential. Nevertheless, many practical parallelisation techniques have been developed [...]

There have been several papers and patents describing their approach, e.g. http://www.cs.ox.ac.uk/dan.olteanu/papers/mnpho-aaai14.pdf