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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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Write jena TDB Query Results into Parquet

I am not sure if it's possible to write the query results of Apache-Jena tdbquery directly into other file formats such as the columnar ones (e.g., parquet, or ORC). Herein, how I use it with CSV, I want it to be one of the other file…
Mohammed Ragab
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Illegal escape sequence value when executing a SPARQL against Jena TDB query via Jena's Java API

I am running an SPARQL* query against Jena's TDB where the result set (DBPedia logs) contains escpace characters. To run the query I use org.apache.jena.query.QueryExecution like the following: query = "SELECT * WHERE { << ?s…
Greenfish
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How do I use multiple writers with tdb?

I'm using tdb to try to get acquainted with database management in C on Linux. Per tdb's description tdb is a Trivial database. In concept, it is very much like GDBM, and BSD's DB except that it allows multiple simultaneous writers and uses locking…
Keya Kersting
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Sharing dataset between Fuseki TDB2 containers

I am trying to share same dataset between more than one Fuseki TDB2 containers. I have mounted same volume to all the container to make sure that it has access to same location and then started the container with same dataset name. However it did…
Rajib Deka
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Why TDB2 "Lock already held" problem occurring from jar file?

I am developing an apache Jena application. It works fine when I run the codes from Intellij IDE but if I generate a jar file and run the jar file in terminal it doesn't work. The error I get: Uncaught exeption ! :…
user4176329
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TDB2Factory connecting dataset

I try to use TDB2Factory to connect dataset (in turtle syntax) at URL address. But this command: Dataset ds = TDB2Factory.connectDataset(loc1); doesnt load any data. There is a problem with syntax or exists another way how to connect dataset from…
IvetX
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Can fuseki be config to use two different type of dataset to created a unioned dataset?

I'm thinking that to create two dataset, one is in memory, which frequently changed, another is tdb, which is read-only, can be created as one dataset, but in the back, which in memory remain in memory, and which in tdb remain in tdb. If not, can…
Gao
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Does Apache Jena evict tdb cache?

I'm using apache jena with TDB. I just read some code from jena 3.9.0, it seems TDB using mmap to speed up query(MappedByteBuffer). But I have seen block(MappedByteBuffer) only grows but not shrik. Does this cause memory problem?
Gao
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How to create a Jena Triple Store based on an existing OWL file using Jena API, Fuseki and TDB?

I am currently working on a project where there is an initial .owl file that contains the base schema for our ontology. We load this file using the Jena API and perform different manipulations on it, such as adding ontology classes and individuals.…
vladek
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how to store data after doing modification using sparql update with Fuseki server

I use fuseki server to query and update my RDF data , there are any methode do save those modifications ? should i use TDB dataset to save modifications ? If yes there are please any exepmle that it can help me ? thanks for your help
jena
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No GRAPHs in Jena TDB

I loaded two .nq files into TDB using the following code: Dataset dataset = TDBFactory.createDataset(""); Model tdb = dataset.getDefaultModel(); for (File file : folder.listFiles()) { …
Janothan
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Empty TDB2 Query Result

I have a problem with the command line tools of Apache Jena. I want to create a tdb2 database for a big turtle file. For this reason I used the tdb2.loader command as follows: tdb2.tdbloader --loc ~/indexer ~/indexer/test.ttl My test.ttl file…
O.Rly
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Loading RDF files using TDB

I'm using Apache Jena TDB to load many files for future reference, when I load using the getDefaultModel method (default model), everything happens normally, but when I try to use a named model the process gets very slow and the CPU reaches 100%,…
Italo Pereira
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Jena Fuseki - Load ttl file into a graph (new or already present) in a dataset

I'm using Apache Jena Fuseki 2.3.0. I need to split my data into different graphs (two), so I have to specify the graph of a dataset to load the data into. I need to use tdbloader but I can't figure out how the graph name can be specified on the…
Bino
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How to deal with data quality issues in Linked Data

I have recently been exploring linked data and I keep running into one issue after the other. To overcome the performance lag while accessing external endpoints, I wanted to store data dumps locally. However, the datasets I come across mostly have…
RDangol
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