Hi Andy,, Thank you for answering my email. The Jena version is (2.11.0) included TDB version (1.0.0). I am using the last DBPedia dump file of size around (64GB). I used “TDBloader2” to load this dump file to TDB store. It loaded (410345971 triples) to TDB store. The total size of TDB files is around (60GB).
I tried all queries you offered, but there is no effect, very long time or no end running. I tried them by using both, local Fuseki server and Jena API in Java application. However, when I tried the same queries by using DBpedia online endpoints, it took seconds (including the query I wrote). I am using DBPedia to find what kind of relations between two entities in online news text (ex. Person, Organisation and Location). This is an example of query that I am using in my application by using DBPedia online endpoint that works fine and very fast. It extracts the relations in a dataset between "Tennessee" location and "Jack Daniel" person. ******************************************************************************* PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT DISTINCT (str(?lbl) AS ?relLBL) WHERE { { ?entity1 ?rel ?entity2 } UNION { ?entity2 ?rel ?entity1 } ?entity1 rdfs:label "Tennessee"@en . ?entity2 rdfs:label "Jack Daniel"@en . ?rel rdfs:label ?lbl FILTER ( lang(?lbl) = "en" ) } the answer of this query by using DBPedia online endpoint is: | relLBL | | birth place | | PLACE OF BIRTH | | death place | **************************************************************************************** I am a PhD student and my reserach is in a critical point because I am tending to use a bigger dataset, Freebase dataset, to extract relations. Because Freebase endpoint does not support SPARQL query language, I have thought that loading its RDF dump file to TDB store and using SPARQL language to extract relations between entities is a solution to my reserach. DBPedia contains triples less than half Trillion and makes TDB very slow so what is about 2.6 Trillion triples in Freebase, could TDB handle it? I read many papers which compare between RDF stores in terms of BigData era. I found that Jena TDB is good enough for my data besides that I have a satisfactory Jena background. How to make Jena TDB fast enough to extract relation from Freebase? I am sorry for this long email, but as I said above, my research is in critical point and I need every little help.Thanks in advance.Abdul From: Andy Seaborne <[email protected]> To: [email protected] Sent: Saturday, 14 March 2015, 19:09 Subject: Re: TDB Optimization One other point: TDB query execution does not, currently, use multiple threads for a single query. In Fuseki, where multiple overlapping requests matter, the cores allow the server to execute requests in true concurrency. Andy
