Hello All, This Jira ticket explains my situation well.
After reading through the following paragraph in https://jena.apache.org/documentation/query/service.html Performance Considerations This feature is a basic building block to allow remote access in the middle of a query, not a general solution to the issues in distributed query evaluation. The algebra operation is executed without regard to how selective the pattern is. So the order of the query will affect the speed of execution. Because it involves HTTP operations, asking the query in the right order matters a lot. Don't ask for the whole of a bookstore just to find book whose title comes from a local RDF file - ask the bookshop a query with the title already bound from earlier in the query. I modified the code to restructure the sequence of call CONSTRUCT { ?s ?p ?o . ?s ?p <http://localhost/target#Doctor> .} WHERE { SERVICE <http://localhost:8084/processor/webresources/rs/sparql> { ?s ?p <http://localhost/traleerdf/db#Physician>. ?s ?p ?o . } SERVICE <http://localhost:8084/processor/webresources/rs/sparql> { ?s ?p ?o } } LIMIT 10 So, the query which returns minimum no of rows is called first and then the second service is executed. This way, the calls to the endpoint are drastically reduced. Thanks for the response Regards Kamalraj On 14 Feb 2014, at 9:07 pm, Olivier Rossel <[email protected]<mailto:[email protected]>> wrote: May be that thread might help: https://issues.apache.org/jira/browse/JENA-449#comment-13651857httpstatus Give us your feedback. On Fri, Feb 14, 2014 at 5:44 AM, Kamalraj Jairam < [email protected]<mailto:[email protected]>> wrote: Hello All, I'm having performance issues with ARQ federated query. ARQ seems to generate multiple select queries to the endpoints when it should just send only 2 queries to the respective endpoints CONSTRUCT { ?s ?p ?o . ?s <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://localhost/target#Doctor> .} WHERE { SERVICE <http://localhost:8084/processor/webresources/rs/sparql> { ?s ?p ?o } SERVICE < http://localhost:8084/processor/webresources/rs/sparql> { ?s ?p ?o . ?s < http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < http://localhost/traleerdf/db#Physician> } } What am i doing wrong? regards Regards, Kamalraj Jairam General Manager - Solutions Development Semantic Software www.semanticsoftware.com.au<http://www.semanticsoftware.com.au/><http://www.semanticsoftware.com.au/> Australian Office: +61-2-9931-7848 Australian Cell: +61-405-203134
