Another observation I note is that there is a common factor within each
UNION:
GRAPH <GraphABaseURI>{
?variableA a graphA:ClassA .
?variableA graphA:propertyA ?variableB .
?variableB dcterms:title ?variableC .
?variableA graphA:propertyB ?variableD .}
Could this be factored out to drive the overall query, and then UNION the
sub-selects on the other conditions?
On Wed, Sep 28, 2016 at 2:06 PM Jerven Tjalling Bolleman
<jerven.bolleman@sib.swiss> wrote:
> Hi Pantelis,
>
> One thing that struck me as an other virtuoso user is
> the joins in the filters.
>
> e.g.
>
> FILTER (?variableE = ?variableH)
>
> I think if you remove all instances of ?variableH with ?variableE
> you should get better results.
>
> Hope that helps.
>
> Regards,
> Jerven
>
> On 28/09/16 14:44, Pantelis Natsiavas wrote:
> > Hi everybody.
> >
> > I have a rather complex SPARQL query, which is executed thousands of
> > times in parallel threads (400 threads). The query is here somewhat
> > simplified (namespaces, properties and variables have been reduced) for
> > readability, but the complexity is left untouched (unions, number of
> > graphs etc.). The query is run against 4 graphs, the biggest of which
> > contains 5561181 triples.
> >
> > PREFIX graphA: <GraphABaseURI:>
> >
> > ASK
> > FROM NAMED <GraphBURI>
> > FROM NAMED <GraphCURI>
> > FROM NAMED <GraphABaseURI>
> > FROM NAMED <GraphDBaseURI>
> > WHERE{
> > {
> > GRAPH <GraphABaseURI>{
> > ?variableA a graphA:ClassA .
> > ?variableA graphA:propertyA ?variableB .
> > ?variableB dcterms:title ?variableC .
> > ?variableA graphA:propertyB ?variableD .
> > ?variableL<GraphABaseURI:propertyB> ?variableD .
> > ?variableD <propertyBURI> ?variableE
> > }
> > .
> > GRAPH <GraphBURI>{
> > ?variableF <propertyCURI>/<propertyDURI> ?variableG .
> > ?variableF <propertyEURI> ?variableH
> > }
> > .
> > GRAPH <GraphCURI>{
> > ?variableI <http://www.w3.org/2004/02/skos/core#notation>
> > ?variableJ .
> > ?variableI <http://www.w3.org/2004/02/skos/core#prefLabel>
> > ?variableK .
> > FILTER (isLiteral(?variableK) && REGEX(?variableK, "literalA",
> "i"))
> > }
> > .
> > FILTER (isLiteral(?variableJ) && ?variableG = ?variableJ) .
> > FILTER (?variableE = ?variableH)
> > }
> > UNION
> > {
> > GRAPH <GraphABaseURI>{
> > ?variableA a graphA:ClassA .
> > ?variableA graphA:propertyA ?variableB .
> > ?variableB dcterms:title ?variableC .
> > ?variableA graphA:propertyB ?variableD .
> > ?variableL<propertyBURI> ?variableE .
> > ?variableL <propertyFURI> ?variableD .
> > }
> > .
> > GRAPH <GraphDBaseURI>{
> > ?variableM <propertyGURI> ?variableN .
> > ?variableM <propertyHURI> ?variableO .
> > FILTER (isLiteral(?variableO) && REGEX(?variableO, "literalA",
> > "i"))
> > }
> > .
> > FILTER (?variableE = ?variableN) .
> >
> > }
> > UNION
> > {
> > GRAPH <GraphABaseURI>{
> > ?variableA a graphA:ClassA .
> > ?variableA graphA:propertyA ?variableB .
> > ?variableB dcterms:title ?variableC .
> > ?variableA graphA:propertyB ?variableD .
> > ?variableL<propertyBURI> ?variableE .
> > ?variableL <propertyIURI> ?variableD .
> > }
> > .
> > GRAPH <GraphDBaseURI>{
> > ?variableM <propertyGURI> ?variableN .
> > ?variableM <propertyHURI> ?variableO .
> > FILTER (isLiteral(?variableO) && REGEX(?variableO, "literalA",
> > "i"))
> > }
> > .
> > FILTER (?variableE = ?variableN) .
> > }
> > . FILTER (isLiteral(?variableC) && REGEX(?variableC, "literalB",
> > "i")) .
> > }
> >
> >
> > I would not expect someone to transform the above query (of course...).
> > I am only posting the query to demonstrate the complexity and all the
> > SPARQL structures used.
> >
> > My questions:
> >
> > 1. Would I gain regarding performance if I had all my triples in one
> > graph? This way I would avoid unions and simplify my query, however,
> > would this also benefit in terms of performance?
> > 2. Are there any kind of indexes that I could built and they could be of
> > any help with the above query? I am not really confident on data
> > indexing, however reading in
> >
> http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtRDFPerformanceTuning#RDF
> > Index Scheme I wonder if the virtuoso 7's default indexing scheme is
> > suitable for queries like the above. While the predicates are defined in
> > the above query's SPARQL triple patterns, there are many triple patterns
> > that have not defined subject or predicate. Could this be a major
> > problem regarding performance?
> > 3. Perhaps there is a SPARQL syntax structure that I am not aware of and
> > could be of great help in the above query. Could you suggest something?
> > For example, I have already improved performance by removing STR() casts
> > and using the isLiteral() function. Could you suggest anything else?
> > 4. Perhaps you could suggest overusing a complex SPARQL syntax structure?
> >
> > Please note that I use Virtuoso Open source edition, built on Ubuntu,
> > Version: 07.20.3214, Build: Oct 14 2015.
> >
> > Regards,
> > Pantelis Natsiavas
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> >
> >
> >
> > _______________________________________________
> > Virtuoso-users mailing list
> > Virtuoso-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/virtuoso-users
> >
>
> --
> -------------------------------------------------------------------
> Jerven Bolleman Jerven.Bolleman@sib.swiss
> SIB Swiss Institute of Bioinformatics Tel: +41 (0)22 379 58 85
> CMU, rue Michel Servet 1 Fax: +41 (0)22 379 58 58
> 1211 Geneve 4,
> Switzerland www.sib.swiss - www.uniprot.org
> Follow us at https://twitter.com/#!/uniprot
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>
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