I tried both queries, with union Graph , and without , and the result is interesting and not ambiguous ( measured with time wget ) :
- with union Graph : around 0.07 second - without union Graph: 12 seconds About the inheritance depth, the main use case currently is to get the foaf:Person when asking for a foaf:Agent . Then other cases are the dbPedia stuff like cites, places . And taxonomic data about species where family, genus, species are modeled by RDF classes, and the depth (8) is like this Kingdom: Plantae <https://en.wikipedia.org/wiki/Plant> (unranked): Angiosperms <https://en.wikipedia.org/wiki/Angiosperms> (unranked): Eudicots <https://en.wikipedia.org/wiki/Eudicots> (unranked): Asterids <https://en.wikipedia.org/wiki/Asterids> Order: Lamiales <https://en.wikipedia.org/wiki/Lamiales> Family: Lamiaceae <https://en.wikipedia.org/wiki/Lamiaceae> Genus: *Salvia <https://en.wikipedia.org/wiki/Salvia>* Species: *S. fruticosa* I would say, generally no deep hierarchy. Here is there the query with union Graph : PREFIX text: <http://jena.apache.org/text#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX form: < http://raw.githubusercontent.com/jmvanel/semantic_forms/master/vocabulary/forms.owl.ttl# > SELECT DISTINCT ?thing ?COUNT WHERE { ?thing text:query ( 'Jean*' ) . GRAPH <urn:x-arq:UnionGraph> { ?thing a ?sub . ?sub rdfs:subClassOf* <http://xmlns.com/foaf/0.1/Person> . OPTIONAL { ?thing form:linksCount ?COUNT. } } } ORDER BY DESC(?COUNT) LIMIT 10 and the one originally posted, more complex, and less efficient ( but same result): PREFIX text: <http://jena.apache.org/text#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX form: < http://raw.githubusercontent.com/jmvanel/semantic_forms/master/vocabulary/forms.owl.ttl# > SELECT DISTINCT ?thing ?COUNT WHERE { ?thing text:query ( 'Jean*' ) . graph ?g1 { ?thing a ?sub . } graph ?g2 { ?sub rdfs:subClassOf* <http://xmlns.com/foaf/0.1/Person> . } . OPTIONAL { graph ?grCount { ?thing form:linksCount ?COUNT. } } } ORDER BY DESC(?COUNT) LIMIT 10 2018-02-08 16:19 GMT+01:00 Andy Seaborne <a...@apache.org>: > > > On 08/02/18 08:39, Jean-Marc Vanel wrote: > >> Hi >> >> I wonder about performance of arbitrary length path in Jena : >> https://www.w3.org/TR/2013/REC-sparql11-query-20130321/#prop >> ertypath-arbitrary-length >> >> For example , here is the query in semantic_forms for searching a string >> with a type class. I added yesterday the rdfs:subClassOf* pattern. >> I wonder if it would not be more efficient with the unionGraph instead of >> numerous GRAPH blocks . >> > > if you try it, please do report on the effect. > > GRAPH <urn:x-arq:UnionGraph> > > Are the rdfs:subClassOf hierarchies very deep? > > As you have it, there is a bit of cross product of ?g1 and ?g2 going on. > > Andy > > >> PREFIX text: <http://jena.apache.org/text#> >> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> >> PREFIX form: < >> http://raw.githubusercontent.com/jmvanel/semantic_forms/mast >> er/vocabulary/forms.owl.ttl# >> >>> >>> >> SELECT DISTINCT ?thing ?COUNT WHERE { >> ?thing text:query ( 'Jean*' ) . >> >> graph ?g1 { >> ?thing a ?sub . >> } >> graph ?g2 { >> ?sub *rdfs:subClassOf** <http://xmlns.com/foaf/0.1/Person> . >> } . >> OPTIONAL { >> graph ?grCount { >> ?thing form:linksCount ?COUNT. >> } } >> } >> ORDER BY DESC(?COUNT) >> LIMIT 10 >> >> >> -- Jean-Marc Vanel http://www.semantic-forms.cc:9111/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me#subject <http://www.semantic-forms.cc:9111/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me> Déductions SARL - Consulting, services, training, Rule-based programming, Semantic Web +33 (0)6 89 16 29 52 Twitter: @jmvanel , @jmvanel_fr ; chat: irc://irc.freenode.net#eulergui
