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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SPARQL query including a subquery on Wikidata gives unexpected results

I know the following SPARQL against Wikidata SPARQL Endpoint query is senseless. A similar query is automatically generated from within my application. Please disregard the conceptual soundness, and let's dig into this strange (for me at least)…
Median Hilal
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How to load rdf data to bigdata using nanosparqlserver

I have downloaded bigdata.war and have deployed it using sesame HTTP API. Now I am not getting as to how should I load rdf triples/provenance with triples to bigdata using nanosparqlserver? I am using sesame HTTP API (using apache tomcat). Can…
Jannat Arora
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Shortest path with SPARQL and blazegraph

This code gives the descendants of Genghis Kahn up to a certain depth (as a graph which can be changed to a table) : PREFIX bd: PREFIX wd: PREFIX wdt:…
Tobi
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SPARQL: Querying Wikidata labels for more than one language

I am trying to get labels in multiple languages from Wikidata's SPARQL endpoint. The following example is given here: SELECT ?country ?country_EN ?country_DE ?country_FR WHERE { ?country wdt:P31 wd:Q185441. # member state of the European…
Udi
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Blazegraph error when running on Windows 10

Failed to run Blazegraph (Java RDF triple store) on Windows 10 using the simple steps from the download page. I have a windows 10 machine with Java JDK 9 installed (See version check below). I downloaded the latest Blazegraph executable jar and then…
aidesigner
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Setting a query timeout in Wikidata api

I've created a local version of the wikidata api using the instructions here, and I'd like to specify a custom timeout to override the 60 second timeout in the official api. I haven't found anything in RWStore.properties, but perhaps I'm missing…
dimid
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SPARQL query: using VALUES inline data or UNION with bigdata store

I have a dataset that looks a bit like: I want to be able to use SPARQL to answer the question: "Which items will I find at someAddress or…
user1685073
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RDF--How do I make a transitive property shift, based on the rdf:type?

I'm trying to find a way to infer/propogate a property based on types to prevent name collision: :AOrder :Store :AStore ; a :OrderType ; :user :AUser . :AStore :name "Store Name"; a :StoreType :AUser :name "Some User"; …
Michael Kohout
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SPARQL query for semantic similarity in Wikidata times out

I'd like to find entities "similar" to John Harrison in Wikidata. My naive SPARQL query always times out. SELECT ?similar ?similarLabel (COUNT(?p) AS ?similarity) WHERE { wd:Q314335 ?p ?o. ?similar ?p ?o. SERVICE wikibase:label {…
rickhg12hs
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force blazegraph to listen on localhost only

The blazegraph.jar contains an older Jetty server that triggers security warnings. Is there a way to force blazegraph to only listen to port 9999 on localhost and not on the general network interface 0.0.0.0? I tried the -Djetty.host=127.0.0.1 but…
wnm3
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Where are blazegraph data files located? Can they be deleted to fix undeletable namespace?

Somehow we have a namespace that is corrupted and cannot be deleted using the webpage for namespaces (that is about the extent of the message you get...). Where are the blazegraph data files located on disk so I can delete them and restart…
wnm3
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Using SPARQL to get the first entity of superclasses of a certain class

I use Jena from Java code and Blazegraph as a server, I have tried to query the first superclass in a path of a certain class, and of course, I didn't use either * or + with the predicate rdfs:subClassOf. The query works well from the Blazegraph…
Mario Raw
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Wikidata on local Blazegraph : Expected an RDF value here, found '' [line 1]

We (Thomas and Wolfgang) have installed locally wikidata and blazegraph following the instruction here : https://github.com/wikimedia/wikidata-query-rdf/blob/master/docs/getting-started.md The mvn package command was successful [INFO]…
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Update or create numeric counters in sparql (UPSERT)

I would like to store a large number of integers in an rdf database (Blazegraph). Those values need to be updated (incremented) with new data, or if missing, created. What's the best way to do that in sparql 1.1? If I was wrtiting it in SQL…
Yuri Astrakhan
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Querying Blazegraph for large resultset

Does Blazegraph support iterating over a large query resultset? For example, given a 200GB Blazegraph database, with constantly running multiple inbound updaters, would it be possible to run a complex SPARQL query that may return a few GBs of data?
Yuri Astrakhan
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