Elasticsearch-rails: How to create a mapping with join type?

[kaibadash]

I'd like to use Join datatype.

I tried like as below.

settings index: {number_of_shards: 1, max_result_window: 10000000, } do
  mappings dynamic: 'false' do
    indexes :my_join_field, type: "join" do
      indexes :relation, { "question" => "answer" }
    end

I got error.

{"type":"mapper_parsing_exception","reason":"Mapping definition for [my_join_field] has unsupported parameters:  [fields : {relation={question=answer, type=text}}]"}}

How can I resolve that?

[runephilosof]

You can see an example of how it can be done in https://github.com/elastic/elasticsearch-rails/blob/master/elasticsearch-model/spec/support/app/parent_and_child_searchable.rb and https://github.com/elastic/elasticsearch-rails/blob/master/elasticsearch-model/spec/elasticsearch/model/adapters/active_record/parent_child_spec.rb

[kaibadash]

Thank you!