Comunica Optional Index Nested Loop RDF Join Actor

An RDF Join actor that optionally joins 2 streams as an index nested loop join.

Bound operations are passed to their source directly if it can look up operations synchronously (IQuerySource#queryBindingsSynchronous).

This module is part of the Comunica framework, and should only be used by developers that want to build their own query engine.

Click here if you just want to query with Comunica.

Install

$ yarn add @comunica/actor-rdf-join-optional-index-nested-loop
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Configure

After installing, this package can be added to your engine's configuration as follows:

{
  "@context": [
    ...
    "https://linkedsoftwaredependencies.org/bundles/npm/@comunica/actor-rdf-join-optional-index-nested-loop/^5.0.0/components/context.jsonld"
  ],
  "actors": [
    ...
    {
      "@id": "urn:comunica:default:rdf-join/actors#optional-index-nested-loop",
      "@type": "ActorRdfJoinOptionalIndexNestedLoop",
      "mediatorJoinSelectivity": { "@id": "urn:comunica:default:rdf-join-selectivity/mediators#main" },
      "mediatorMergeBindingsContext": { "@id": "urn:comunica:default:merge-bindings-context/mediators#main" }
    }
  ]
}
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Config Parameters

• mediatorJoinSelectivity: A mediator over the RDF Join Selectivity bus.
• mediatorMergeBindingsContext: A mediator over the Merge Bindings Context bus.
• selectivityModifier: Multiplier for selectivity values, which defaults to half the one of the optional bind join, so that this actor is preferred where both apply. (defaults to 0.0000005)