Your query asked for all quads from the database, and then returned the distinct graph values from them. The query I gave you simply returns the names of all graphs - whether they contain triples or not. The latter is a simple scan of the collection lexicon, where as the former involves reading all triples in the database and joining them against the collection lexicon to find the graphs they are in.
John On 20/04/17 17:11, Ghislain Atemezing-Pro wrote: Thanks John! It works. But is there any rationale behind the use of those queries instead of the one I was using? Best, Ghislain Le jeu. 20 avr. 2017 à 18:00, John Snelson <[email protected]<mailto:[email protected]>> a écrit : Try this: select ?g { graph ?g {} } or even this: select (count(?g) as ?count) { graph ?g {} } John On 20/04/17 16:46, Ghislain Atemezing-Pro wrote: Hi all, I am trying to make some basic statistics using SPARQL queries on my endpoint backed by MarkLogic. Today, I just wanted to retrieve the number of named graphs with the following query: select distinct ?g where { graph ?g { ?s ?p ?o } } I realize that the operation works fine when I limit to 2 (why?) and then for the rest, I have a time exceed limit. Did someone also experience this issue before? Thanks in advance. Best, Ghislain -- -------------------------------------------- Ghislain A. Atemezing, Ph.D R&D Engineer SemWeb @ Mondeca, Paris, France Labs: http://labs.mondeca.com Tel: +33 (0)1 4111 3034<tel:+33%201%2041%2011%2030%2034> Web: www.mondeca.com<http://www.mondeca.com> Twitter: @gatemezing About Me: http://atemezing.org _______________________________________________ General mailing list [email protected]<mailto:[email protected]> Manage your subscription at: http://developer.marklogic.com/mailman/listinfo/general -- John Snelson, Principal Engineer http://twitter.com/jpcs MarkLogic Corporation http://www.marklogic.com _______________________________________________ General mailing list [email protected]<mailto:[email protected]> Manage your subscription at: http://developer.marklogic.com/mailman/listinfo/general -- -------------------------------------------- Ghislain A. Atemezing, Ph.D R&D Engineer SemWeb @ Mondeca, Paris, France Labs: http://labs.mondeca.com Tel: +33 (0)1 4111 3034 Web: www.mondeca.com<http://www.mondeca.com> Twitter: @gatemezing About Me: http://atemezing.org _______________________________________________ General mailing list [email protected]<mailto:[email protected]> Manage your subscription at: http://developer.marklogic.com/mailman/listinfo/general -- John Snelson, Principal Engineer http://twitter.com/jpcs MarkLogic Corporation http://www.marklogic.com
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