[det]rdf_update_duplicatesUpdate the duplicate administration of the RDF store. This marks every
triple that is potentionally a duplicate of another as duplicate. Being
potentially a duplicate means that subject, predicate and object are
equivalent and the life-times of the two triples overlap.
The duplicates marks are used to reduce the administrative load of
avoiding duplicate answers. Normally, the duplicates are marked using a
background thread that is started on the first query that produces a
substantial amount of duplicates.