Build a reverseStatement index only centered on a subset of well defined (transitive?) properties

[oterrier]

Building such an index for all the statements is not manageable due to the explosion of the wikidata recently (more than 90M items) but it could be interesting to restrict its scope to a subset of properties that are used for transitive relations in WD like:

• P279 (subclass of)

Most of the time we would like to express things like in SPARQL
?item wdt:P31/wdt:P279* ?class. This means that there’s one “instance of” and then any number of “subclass of” statements between the item and the class.
My intuition is also that most of the time we want to express something like that:

1. an initial property seed (P31 or P106)
2. then follow the "subclass of" hierarchy (P279*)

For that a reverseP279Statement db could do the job

Best regards
Olivier