- From: Denis Gaertner <denis_gaertner@gmx.net>
- Date: Mon, 19 Jun 2006 20:29:44 +0200
- To: public-sparql-dev@w3.org
Hi! I got some questions concerning performance optimization in sparql queries. Since I couldn't find any good information on the net about this(please correct me if this is wrong) I thought this might be the right place for it. So I am wondering how the structure of a complex query affects the processing and query time. You can group Graphpatterns to an arbitrarily depth and I'd like to know if a structure which is equivalent maybe to something like DNF or CNF in feature sets could help. So for example : { {?s p "o"} UNION {?s p2 "o2"} } {?s p3 "o3"} becomes {?s p "o" . ?s p3 "o3"} UNION {?s p2 "o2" . ?s p3 "o3"} Now this put in a large scale means breaking down lots of levels into fewer. Is this of advantage or is the rdf graph structure not suitable for this kind of transformation? Or is it solely a question of implementation? And another thing is about constraints. Is it better to put them into a group or to collect them and put them at the end if possible? So for instance: {?s p ?o1 FILTER (?o1...)} {?s p2 ?o2 FILTER (?o2...)} or {?s p ?o1} FILTER (?o1...) {?s p2 ?o2} FILTER (?o2...) or {?s p ?o1} {?s p2 ?o2} FILTER (?o1... && ?o2...) So this is it and since I don't know anything on how these queries are processed I am not able to figure that out by myself. Thanks Denis
Received on Tuesday, 20 June 2006 05:40:27 UTC