Hi Claus, I see the behaviour you report running the two queries again http://dbpedia.org/sparql , but running against http://lod.openlinksw.com/sparql the roles are reversed with the bif:contains query completing in about 1 sec :
http://lod.openlinksw.com/sparql/?default-graph-uri=&qtxt=Select+%3Fx+%7B%0D%0A++%3Fx+%3Chttp%3A%2F%2Fwww.w3.org%2F1999%2F02%2F22-rdf-syntax-ns%23type%3E+%3Chttp%3A%2F%2Fwww.w3.org%2F2002%2F07%2Fowl%23Class%3E+.%0D%0A++%3Fx+%3Chttp%3A%2F%2Fwww.w3.org%2F2000%2F01%2Frdf-schema%23label%3E+%3Fv_3+.%0D%0A++Filter%28%3Cbif%3Acontains%3E%28%3Fv_3%2C+%22airport%22%29%29+.%0D%0A++Filter%28langMatches%28lang%28%3Fv_3%29%2C+%22en%22%29%29+.%0D%0A%7D++Limit+10&format=text%2Fhtml&CXML_redir_for_subjs=121&CXML_redir_for_hrefs=&timeout=30000&debug=on and the regex query taking 20+ secs to complete: http://lod.openlinksw.com/sparql/?default-graph-uri=&qtxt=Select+%3Fx+%7B%0D%0A++%3Fx+%3Chttp%3A%2F%2Fwww.w3.org%2F1999%2F02%2F22-rdf-syntax-ns%23type%3E+%3Chttp%3A%2F%2Fwww.w3.org%2F2002%2F07%2Fowl%23Class%3E+.%0D%0A++%3Fx+%3Chttp%3A%2F%2Fwww.w3.org%2F2000%2F01%2Frdf-schema%23label%3E+%3Fv_3+.%0D%0A++Filter%28regex%28%3Fv_3%2C+%22airport%22%2C+%22i%22%29%29+.%0D%0A++Filter%28langMatches%28lang%28%3Fv_3%29%2C+%22en%22%29%29+.%0D%0A%7D++Limit+10&format=text%2Fhtml&CXML_redir_for_subjs=121&CXML_redir_for_hrefs=&timeout=30000&debug=on So something to look into against the dbpedia endpoint , but not against lod ... Best Regards Hugh Williams Professional Services OpenLink Software, Inc. // http://www.openlinksw.com/ Weblog -- http://www.openlinksw.com/blogs/ LinkedIn -- http://www.linkedin.com/company/openlink-software/ Twitter -- http://twitter.com/OpenLink Google+ -- http://plus.google.com/100570109519069333827/ Facebook -- http://www.facebook.com/OpenLinkSoftware Universal Data Access, Integration, and Management Technology Providers On 19 Aug 2014, at 12:20, Claus Stadler <cstad...@informatik.uni-leipzig.de> wrote: > Hi, > > I noticed the following issue on the DBpedia endpoint and the LOD cache > (http://dbpedia.org/sparql, http://lod.openlinksw.com/sparql): > I did not have time to try it against a develop7 git branch. > > The following query works as expected and returns fast: It apparently scans > the approx. 600 classes and filters them by their label matching the regex: > > Select ?x { > ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> > <http://www.w3.org/2002/07/owl#Class> . > ?x <http://www.w3.org/2000/01/rdf-schema#label> ?v_3 . > Filter(regex(?v_3, "airport", "i")) . > Filter(langMatches(lang(?v_3), "en")) . > } Limit 10 > > > > The following query takes very long to complete. Apparently the query planner > decides to start with bif:contains, thereby scanning all instances that have > 'airport' in their name - which is a much larger set than filtering just by > the classes first: > > Select ?x { > ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> > <http://www.w3.org/2002/07/owl#Class> . > ?x <http://www.w3.org/2000/01/rdf-schema#label> ?v_3 . > Filter(<bif:contains>(?v_3, "airport")) . > Filter(langMatches(lang(?v_3), "en")) . > } Limit 10 > > I am wordering if there are already planned enhancements for this issue. > > > Cheers, > Claus > > -- > Dipl. Inf. Claus Stadler > Department of Computer Science, University of Leipzig > Research Group: http://aksw.org/ > Workpage & WebID: http://aksw.org/ClausStadler > Phone: +49 341 97-32260 > > > ------------------------------------------------------------------------------ > _______________________________________________ > Virtuoso-users mailing list > Virtuoso-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/virtuoso-users
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