the elasticsearch-rails client provides a relatively simple interface for the Elasticsearch Bulk API, which can speed up the indexing

fast_elasticsearch_importer.rb

# A FASTER IMPORTER
#
# the built-in import is not very efficient.
# It grabs every record, builds the ActiveRecord object
# and calls #as_indexed_json on it.
#
# for large sets of data that spans multiple relations,
# this can take a lot of time to complete.
#
# the elasticsearch-rails client provides a relatively simple interface for
# the Elasticsearch Bulk API, which can speed up this process.
#
# usage:
#
# => FastElasticsearchImporter.new(Model1, Model2, Model3).import!
#
class FastElasticsearchImporter
  attr_accessor :client, :klasses

  def initialize(*klasses)
    @klasses = klasses
  end

  def client
    @client ||= klasses.first.__elasticsearch__.client
  end

  def target_index
    klasses.first.index_name
  end

  def settings
    with_all_klasses do |klass, _hash|
      _hash.deep_merge! klass.__elasticsearch__.settings.to_hash
    end
  end

  def mappings
    with_all_klasses do |klass, _hash|
      _hash.deep_merge! klass.__elasticsearch__.mappings.to_hash
    end
  end

  def with_all_klasses(&block)
    klasses.each_with_object({}) { |klass, _hash| block.call(klass, _hash) }
  end

  def create_index
    if client.indices.exists(index: target_index)
      Logger.new(STDOUT).info "index: #{target_index} already exists"
    else
      Logger.new(STDOUT).info "creating index: #{target_index}"
      client.indices.create(index: target_index, body: { settings: settings, mappings: mappings })
    end
  end

  def import!
    create_index
    import
  end

  def import
    klasses.each do |klass|
      klass.includes(*associations(klass)).find_in_batches do |models|
        Logger.new(STDOUT).info "importing #{klass.document_type} with associated #{associations(klass)}"
        client.bulk({
          index: target_index,
          type: klass.document_type,
          body: prepare_documents(models)
        })
      end
    end
  end

  def associations(klass)
    klass.__elasticsearch__
      .mapping
      .to_hash[klass.document_type.to_sym].fetch(:properties)
      .select { |k, h| h[:type] == 'nested' || h[:type] == 'object' }
      .keys
  end

  def prepare_documents(models)
    models.map do |model|
      { index: { _id: model.id, data: model.as_indexed_json } }
    end
  end
end

Thx, it helps a lot to speedup elasticsearch import

@toomus wow, didn't even remember that I have written this code :D
glad you found it and that it was useful to you