Comunica Minus Hash RDF Join Actor

An RDF Join actor that anti-joins (minus) 2 streams using the hash join algorithm. Depending on how this actor is configured, it either does or does not support streams that can have undefined values.

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-minus-hash

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-minus-hash/^4.0.0/components/context.jsonld"
  ],
  "actors": [
    ...
    {
      "@id": "urn:comunica:default:rdf-join/actors#minus-hash",
      "@type": "ActorRdfJoinMinusHash",
      "mediatorJoinSelectivity": { "@id": "urn:comunica:default:rdf-join-selectivity/mediators#main" },
      "canHandleUndefs": true
    }
  ]
}

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.