whichdb

Mulgara

discontinued

by Mulgara Project · since 2006 · also known as Kowari

Pure-Java RDF triplestore forked from Kowari, with SPARQL and iTQL; dormant since its 2014 release.

rdf / triple storedatabase engineopen source (copyleft)legacy
Website Source★ 48 Compare Find similar

discontinued. No release since 2.1.13 (Feb 2014); the GitHub repository is dormant. Use Apache Jena TDB, RDF4J or Oxigraph.

Overview

Mulgara is a transactional RDF triplestore written entirely in Java, forked in 2006 from Tucana's Kowari after Northrop Grumman, which had bought Tucana and owned the Kowari trademark, threatened a developer over new releases. Instead of sitting on a relational database it keeps its own indexes of subject-predicate-object statements, answers SPARQL and the older iTQL language, supports JTA transactions, and integrates with the Jena and Sesame APIs. Development slowed after 2012 and the last release, 2.1.13, was a small auditing fix in February 2014; the code now sits on GitHub with only token activity since. Choose Apache Jena TDB, RDF4J, Oxigraph or a commercial store for anything current.

Knowledge graphMetadata & config

Strengths & trade-offs

Strengths

  • +Native triple indexes rather than an RDF layer over SQL
  • +Transactional, with JTA/XA integration for Java applications
  • +Jena and Sesame compatibility eased swapping it into existing code

Trade-offs

  • −No releases since 2014 and no active maintainers
  • −SPARQL 1.1 support is incomplete compared with current stores
  • −OSL 3.0 licensing is unusual and less permissive than Apache-licensed peers

Great for

  • +Maintaining legacy semantic-web applications built on it
  • +Historical reference for Java triplestores

Think twice for

  • −New knowledge-graph projects
  • −Large-scale SPARQL workloads

Capabilities

Native or official first-party support · 3 of 25 tracked

✓Transactions
✓Joins
✓Durable persistence
–Secondary indexes
–Full-text search
–Vector search
–Geospatial
–JSON
–Change data capture
–Triggers
–Stored procedures
–Materialized views
–TTL / expiry
–Pub/Sub
–Columnar storage
–In-memory
–Compression
–Encryption at rest
–Role-based access
–Time travel
–Branching
–Online schema changes
–Streaming ingest
–Offline sync
–Runs in WebAssembly

Scale & consistency

Comfortable data size
Small · ≤ 100 GB
Horizontal scaling
None
Multi-region
No
Transactions
Full ACID
Consistency
Strong
Schema
Schemaless
Architecture
Client server, Embedded
Query languages
SPARQL, iTQL

Deployment

Self-hosted Vendor-managed cloud Serverless Embedded Edge Kubernetes operator

Ecosystem

apis & protocolsSPARQL protocol, Jena API, Sesame API, JTA
client languagesJava

Alternatives to Mulgara

Compare all→
Apache Jena TDBRDF / Triple Store18.9

Apache Jena's native RDF store, embeddable in Java or served over SPARQL with Fuseki.

mulgara vs apache-jena-tdb →
Eclipse RDF4JRDF / Triple Store10.6

Eclipse Foundation's Java RDF framework with native, LMDB and in-memory SPARQL stores.

mulgara vs eclipse-rdf4j →
OxigraphRDF / Triple Store15.1

Small, fast SPARQL database in Rust that embeds in Rust, Python and JavaScript or runs as a server.

mulgara vs oxigraph →
OpenLink VirtuosoRDF / Triple Store19.5

Hybrid SQL/RDF engine that runs many of the largest public SPARQL endpoints.

mulgara vs virtuoso →
BlazegraphRDF / Triple Store10.2

Abandoned Java RDF/SPARQL store, still known as the engine behind Wikidata Query Service.

mulgara vs blazegraph →
ConceptBase.ccObject1.4

Deductive object base for metamodeling, built on O-Telos with Datalog rules and unlimited meta-levels.

mulgara vs conceptbase →

Mulgara FAQ

What is Mulgara?

Mulgara is a RDF / triple store database by Mulgara Project, first released in 2006. Mulgara is a transactional RDF triplestore written entirely in Java, forked in 2006 from Tucana's Kowari after Northrop Grumman, which had bought Tucana and owned the Kowari trademark, threatened a developer over new releases. Instead of sitting on a relational database it keeps its own indexes of subject-predicate-object statements, answers SPARQL and the older iTQL language, supports JTA transactions, and integrates with the Jena and Sesame APIs. Development slowed after 2012 and the last release, 2.1.13, was a small auditing fix in February 2014; the code now sits on GitHub with only token activity since. Choose Apache Jena TDB, RDF4J, Oxigraph or a commercial store for anything current.

Is Mulgara open source?

Yes. Mulgara is open source. License: Open Software License 3.0 (newer code Apache 2.0).

Does Mulgara support ACID transactions?

Yes. Mulgara supports full ACID transactions, with strong consistency.

Does Mulgara scale horizontally?

Mulgara does not scale horizontally; it runs on a single node, so you scale it up rather than out. It is comfortable at small scale (≤ 100 GB).

How can I run Mulgara?

You can self-host it and embed it in your application.

What is Mulgara best for?

Mulgara is a strong fit for maintaining legacy semantic-web applications built on it and historical reference for Java triplestores. Think twice for new knowledge-graph projects.

What are the best alternatives to Mulgara?

Common alternatives to Mulgara include Apache Jena TDB, Eclipse RDF4J, Oxigraph, OpenLink Virtuoso and Blazegraph. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.

Is Mulgara still maintained?

Mulgara is discontinued. No release since 2.1.13 (Feb 2014); the GitHub repository is dormant. Use Apache Jena TDB, RDF4J or Oxigraph.

How popular is Mulgara?

Mulgara ranks #514 of 844 databases on the WhichDB Score (1.8/100), and #13 among RDF / triple store databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.