Comunica Optional Hash RDF Join Actor

An RDF Join actor that uses hash joins and can handle optional patterns. A comunica Optional Hash RDF Join Actor.

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-hash
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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-hash/^1.0.0/components/context.jsonld"
  ],
  "actors": [
    ...
    {
      "@id": "urn:comunica:default:rdf-join/actors#optional-hash",
      "@type": "ActorRdfJoinOptionalHash",
      "mediatorJoinSelectivity": { "@id": "urn:comunica:default:rdf-join-selectivity/mediators#main" },
      "canHandleUndefs": true,
      "blocking": true
    }
  ]
}
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Config Parameters

• mediatorJoinSelectivity: A mediator over the RDF Join Selectivity bus.
• canHandleUndefs: If this actor can handle undefined values. If false, performance will be slightly better.
• blocking: If the join will block when collecting the optional stream. If true, performance will be better.