Hi Ivan, hi Hugh, ok, I wasn't aware of the need for additional indices for multiple graph RDF queries. I solved my issue by creating two bitmap indices (P,O,G,S) and (P,S,O,G).
Thanks for your help, Mirko Am 22.11.2009 um 06:34 schrieb Ivan Mikhailov: > Hello Mirko, > > What indexes do you have? You may need at least bitmap SPOG index for > the first query. The default layout (only two indexes) works for queries > taht have all graphs fixed (or calculated before use), but not for all > other queries. > > Best Regards, > > Ivan Mikhailov > OpenLink Software > http://virtuoso.openlinksw.com > > > On Fri, 2009-11-20 at 10:30 +0100, Mirko wrote: >> Hi, >> I have a SPARQL query which performes well when querying a single graph but >> "the estimated execution time exceeds the time limit of 400 (secs)" when >> querying two graphs. This is also true if the second graph is empty. Why is >> this the case / how can I fix this? >> >> Query A (performes well): >> >> SELECT ?description FROM <http://localhost/graphA> WHERE { ?recource >> <http://purl.org/dc/terms/subject> <http://localhost/someElement> . >> ?recource <http://purl.org/dc/terms/subject> ?relatedElement . >> ?relatedElement <http://purl.org/dc/terms/description> ?description . >> ?relatedElement <http://localhost/score> ?score } ORDER BY DESC (?score) >> LIMIT 4 >> >> query B (times out): >> >> SELECT ?description FROM <http://localhost/graphA> FROM >> <http://localhost/graphB> WHERE { ?recource >> <http://purl.org/dc/terms/subject> <http://localhost/someElement> . >> ?recource <http://purl.org/dc/terms/subject> ?relatedElement . >> ?relatedElement <http://purl.org/dc/terms/description> ?description . >> ?relatedElement <http://localhost/score> ?score } ORDER BY DESC (?score) >> LIMIT 4 >> >> -->"The estimated execution time 664 (sec) exceeds the limit of 400 (sec)." >> >> Regards, >> -Mirko >> ------------------------------------------------------------------------------ >> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day >> trial. Simplify your report design, integration and deployment - and focus >> on >> what you do best, core application coding. Discover what's new with >> Crystal Reports now. http://p.sf.net/sfu/bobj-july >> _______________________________________________ >> Virtuoso-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/virtuoso-users >
