Questions tagged [blazegraph]

Blazegraph is an open-source RDF/graph database capable of clustered deployment. This tag is specific for questions on the database API. RDF and SPARQL are often related technologies.

Overview

Blazegraph is an open-source, ultra-scalable, high-performance graph database written in Java. It supports various technologies such as:

Blazegraph offers different operating modes (triples, provenance, and quads) and either operates as an embedded database or over a client/server REST API.

Blazegraph supports up to 50 billion edges on a single machine and has a high availability and scale-out architecture. It is in production use for Fortune 500 customers such as EMC, Autodesk, and many others. It was selected by the Wikimedia foundation to power their Wikidata query service.

Documentation links

The official Blazegraph website can be found here. In-depth technical details on the graph database can be found in the official Blazegraph Wiki. The Blazegraph API itself is documented on GitHub.

Background information on the big-data architecture, internals, and deployment models can be found in several white papers in the Blazegraph Blog.

When to use this tag

Please use the tag on questions about the database API. If you have a more general question to which an answer might not necessarily depend on the Blazegraph API, please consider including or .

If you want to discuss or suggest Blazegraph features, please do it via the Blazegraph contact page.

Related tags

Adapted from the Blazegraph website and the Blazegraph Wiki.

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Error 503 while accessing /bigdata/dataloader at wikidata local

I get this error when running the following command: $ ./loadRestAPI.sh -n wdq -d `pwd`/data/split/wikidump-000000001.ttl.gz See https://github.com/wikimedia/wikidata-query-rdf/blob/master/docs/getting-started.md Loading with…
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SPARQL Update: Underscore not allowed in language tag

I am trying to insert data into blazegraph using the 'Update' tab of blazegraph workbench. Below is a sample code snippet: INSERT DATA { ns:MyNode ns:hasValue "MyValue"@en_us } I am specifying language tag with @ symbol. However, it throws…
whitehat
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Connect to RDF4J server with Sesame library?

I am working on a project that primarily uses Blazegraph as a back-end, and from what I understand, that locks me into a relatively old Sesame (2.7.12). The project has another component that can use an embedded Sesame, or a free-standing Sesame OR…
Mark Miller
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Can Blazegraph work with the Jena framework?

I am looking for a high availability/scale-out triple store that works with the Jena framework and came across Blazegraph. Does Blazegraph have an adaptor for the Jena framework? If not, what are high availability RDF stores that can work with the…
Lin
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Possible Reasons for InstantiationError in Jetty's SocketAddressResolver

I am trying to use a remote instance of the graph database Blazegraph, which requires a call to the constructor of a RemoteRepositoryManager. The call looks as follows (serviceURL is the address of my remote Blazegraph server): val repo = new…
hayfreed
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How does a triplestore decide whether to add "background" triples?

I use a few different triplestores, and code in R and Scala. I think I'm seeing some differences in: whether the triplestores include triples other than the ones I explicitly loaded. the point at which these "background" triples might be…
Mark Miller
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Using functions in Blazegraph

I see some functions documented in Blazegraph, for instance in cern.jet.math.Function: https://blazegraph.github.io/database/apidocs/index.html?cern/jet/math/package-summary.html I am wondering whether it is possible to use these functions in a…
Finn Årup Nielsen
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Abysmal update performance with a very simple query in Blazegraph 2.1.4

The following update query takes 1.7 seconds in Blazegraph: DELETE { :count ?existingObject} INSERT { :count "19" . } WHERE { :count? ?existingObject} The query is part…
Navigateur
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Blazegraph INSERT DATA crashes with NoSuchMethodError

In Blazegraph I attempted the following query: INSERT DATA { :comment . } and it crashes with the following exception trace: java.lang.NoSuchMethodError:…
Navigateur
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IOException Loading Data into BlazegraphEmbedded

I'm having an issue loading my Blazegraph properties file into an embedded instance. When I try to import my .properties file into my Java class, I get the following error: Exception in thread "main" java.io.IOException: Stream closed at…
hayfreed
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Simple SPARQL query does not return any results

I am just getting up and running with Blazegraph in embedded mode. I load a few sample triples and am able to retrieve them with a "select all" query: SELECT * WHERE { ?s ?p ?o } This query returns all my sample…
jeff
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Blazegraph create namespace via REST API

I am running Blazegraph 2.1.1 from the command line. The web interface works fine, so do many GET operations. I want to create a new namespace via the REST API. I run Blazegraph with this command: java -server -Xmx4g…
Wolfgang
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Blazegraph REST POST request not working when translated into Java

I am using underlying methodology to post RDF data into Bazegraph, but unfortunately I am not able to find any data when I do select * {?s ?p ?o} in a query on the Blazegraph UI. Curl command for post request: curl -X POST -H…
Varun Tahin
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Gremlin: Blazegraph Remote

I am trying to get the pipeline up and running with the following setup: Blazegraph 2.1.1 (remote) Tinkerpop 2 (bigdata-blueprints 2.0.0, BlazeGraph-Gremlin 1.0.0, bigdata-core 2.0.0) Language: Java I have been able to use the Blueprints API for…
Varun Tahin
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How can I create a rule in Blazegraph with NOT EXISTS constraint?

This question is related to the Blazegraph Java samples. I want to create a rule with a SPARQL NOT EXISTS clause. This Blazegraph rule sample provides a constraint clause that checks for IsLiteral(). I want to implement a rule that provides the…
ndw37
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