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Questions tagged [tdb]

TDB is an open source RDF database developed and maintained by the Apache Jena project

TDB is an open source RDF database developed and maintained by the Apache Jena project. It is a Java based embedded database that may be exposed over HTTP using the Fuseki Server also from the Apache Jena project.

Features

It's features includes the following:

  • Persisting RDF Triples or Quads
  • Full SPARQL execution
  • Write ahead logging to provide serializable transactions and fault tolerance

Scalability and Performance

TDB typically scales up to datasets of a few hundred million triples or quads.

Compared to commercial alternatives TDB is often less scalable compared primarily because while it is persisted to disk it is fundamentally designed as an in-memory database. It relays heavily on RAM caches and memory mapped files so scalability tends to be limited by machine RAM.

Also TDB does not have any option of a clustered mode so cannot be scaled horizontally without additional technologies (e.g. manually created replicas and load balancers)

TDB is typically included in the Berlin SPARQL Benchmark Results for those interested in comparative performance data.

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How to configure fuseki jena to use a reasoner and TDB + tdb:UnionDefaultGraph

Context i am new to fuseki, i am currently using it in a project, the main idea is: start the server with a pre-defined ontology (turtle file) + a reasoner I process files with python, and for each file, I generate an rdf graph that I put in a…
kam13
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Jena Full-text search using ElasticSearch problem

i've a Graph DB in Jena-Fuseki and i'm trying to index this DB using ElasticSearch cluster , i'm following that link https://jena.apache.org/documentation/query/text-query.html and when i run this command : java -cp ./fuseki-server.jar…
Sarah S. Abulwafa
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What indices does jena TDB2 use?

I am trying to find out what indices TDB2 builds. I found out by the code that it uses B+ trees to store them on disc but I didn't get what they contain and how they are used. So my detailed questions are: For which collation order of RDF triples…
A. Bigerl
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Low Performance for SPARQL Queries to Fuseki on TDB

I have bulk loaded the wikidata dump using tdbloader2. And now I am trying to make SPARQL queries. A query like this runs very slowly(can not be finished in more than 24 hours), though it works on https://query.wikidata.org/ : PREFIX rdfs:…
Romulus Libertas
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Can we create multiple datasets in single TDB directory

String directory = "directoryPath"; Dataset dataset = TDBFactory.createDataset(directory); Dataset datasetnew = TDBFactory.createDataset(directory); Is the dataset a reference to the TDB directory or it's like a folder inside the TDB directory?…
Shreshtha Garg
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SPARQL query works in Fuseki but not in Jena TDB

I have my data organised in multiple graphs. The graph in which a triple is saved matters. The data structure is complicated but it can be simplified like this: My store contains cakes, where there's a hierarchy of different cake types, all…
casualcoder
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Fuseki 2 low performance

I have stored 80GB triples using FUSEKI 2 (latest version), which is actually a DbPedia dump. My problem happens when I run the following query. It is taking more than 5 minutes to return whereas at Snorql it takes less than one second. SELECT …
user7806
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Apache Jena TDB with MySQL

I am working on the semantic web and use TDB for RDF storage.Is it possible that we could use TDB with MySQL Workbench and execute semantic queries against TDB data in Workbench ? I went through Apache Jena TDB tutorial but could not find anything…
John Doe
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How to fix Java error Unsupported major.minor version 52.0 when using Apache Jena tdbloader

On a Apache Jena 3.1.0 on Ubuntu 14.04, while trying to use tdbloader to load triples to a triple store, I've got the following error: tdb/tdbloader : Unsupported major.minor version 52.0 Any hints appreciated.
Alan Tygel
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Persisting data in Jena TDB triple store

I am using Jena TDB to persist RDF data. Before this I searched how to persist data in TDB and I came through the question at this link. Answer provided by Ryan clearly mentions the difference between various concepts, and one of the point I got…
Haroon Lone
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migrate samba domain to CTDB

I am trying to migrate samba domain controller (version 3.6, passdb backend = tdbsam) to a new clustered environment with CTDB (same samba version). I have a functional ceph storage and the ctdbd configured according to the documentation. However,…
Marko
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Strange error in apache tomcat?

I am using apache tomcat with eclipse keplee .this is my jsp file which runs a java file which queries from tdb using sparql . jsp file : <%@ page import="check.test4query" %> <% test4query demo = new test4query(); …
cooljohny
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Apache JENA TDB files locked after creation with web application

I am using JENA to create a triple store (TDB functionality) with the following code: public void createTDBFromOWL() { Dataset dataset = TDBFactory.createDataset(newTripleStoreLocation); dataset.begin(ReadWrite.WRITE); try { …
Nick
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How could I store multiple ontologies in TDB

I am working on a project which need to save multiple ontologies in one TDB. I tried to do it in my own way, but it didn't work. Help me please..If you know how to use TDB , could you post the code applied to my code? String directory =…
user3194152
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How does Apache TDB store RDF data?

According to the Apache website TDB 'can be used as a high performance RDF store on a single machine'. Reading the documentation I don't see where it stores anything. Is it simply storing each resource in its own file within a defined directory as…
WildBill
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