Thank you.
Now I have loaded data using method tdbloader.main(....), and it has
created me index and stats.
I have a query which I am executing, and I feel like the optimizer is not
optimising the query. Can you advice me if I am using it the right way ?
This is the method;
public void testLUBMQuery1_original() {
long duration = 0l;
Date startTime, endTime;
startTime = new Date();
String sparqlQueryString = "PREFIX ub: <
http://swat.cse.lehigh.edu/onto/univ-bench.owl#> "
+ "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> "
+ "SELECT ?X ?Y ?Z WHERE { "
+ "?Z ub:subOrganizationOf ?Y. "
+ "?Y rdf:type ub:University. "
+ "?Z rdf:type ub:Department. "
+ "?X ub:memberOf ?Z. "
+ "?X rdf:type ub:GraduateStudent. "
+ "?X ub:undergraduateDegreeFrom ?Y. }";
Query query = QueryFactory.create(sparqlQueryString);
//Tried with and without the Algebra step
Op op = Algebra.compile(query) ;
query = OpAsQuery.asQuery(op);
QueryExecution qexec = QueryExecutionFactory.create(query, dataset);
ResultSet results = qexec.execSelect();
ResultSetFormatter.out(results);
endTime = new Date();
duration = endTime.getTime() - startTime.getTime();
System.out.println(query.toString());
System.out.println("Original Query 1 Duration: " + duration );
}
Thanks Again.
Best,
Ganesh
On 10 January 2017 at 11:37, Andy Seaborne <[email protected]> wrote:
>
>
> On 09/01/17 19:40, A. Soroka wrote:
>
>> The layout of the statistics file is documented here:
>>
>> https://jena.apache.org/documentation/tdb/optimizer.html#
>> statistics-rule-file
>>
>> tdbloader and tdbloader2 are the CLI utilities for building TDB
>> databases, but they are written in Java and can be used in Java.
>>
>> https://jena.apache.org/documentation/tdb/commands.html#tdbloader
>>
>>
> Jena is open source and maven central has source artifacts that you IDE
> will automatically attach to your projects.
>
> See the package:
> org.apache.jena.tdb.solver.stats;
>
> Andy
>
>
> ---
>> A. Soroka
>> The University of Virginia Library
>>
>> On Jan 9, 2017, at 2:36 PM, Ganesh Selvaraj <[email protected]>
>>> wrote:
>>>
>>> Hi All,
>>>
>>> I am using Jena TDB for my work. So far I could not find much
>>> documentation
>>> on data indexing and statistics building for Jena TDB.
>>>
>>> I would prefer doing it via a Java API.
>>>
>>> Any help/documentation is appreciated.
>>>
>>> Thanks
>>> Ganesh
>>>
>>
>>
