The GraphDB Connectors provide extremely fast keyword and faceted (aggregation) searches that are typically implemented by an external component or service, but have the additional benefit of staying automatically up-to-date with the GraphDB repository data.

The Connectors provide synchronisation at the entity level, where an entity is defined as having a unique identifier (URI) and a set of properties and property values. In terms of RDF, this corresponds to a set of triples that have the same subject. In addition to simple properties (defined by a single triple), the Connectors support property chains. A property chain is defined as a sequence of triples where each triple’s object is the subject of the subsequent triple.

GraphDB EE comes with the following connector implementations:

Features Comparison Table:

Feature Lucene Solr Elasticsearch
FTS search
Simple facets
Snippet extraction
Limit and offset
Fixed range facets
Variable range facets
Nested facets


  • terms
  • histogram
  • range
  • min/max
  • sum
  • average
  • count
  • standard deviation
  • variance
  • sum of squares