Replicas and multiple indices

Learn how to use replicas and multiple indices with the Algolia gem.

Replica indices

Algolia uses one ranking strategy per index. If you want to provide more ranking or sorting strategies, add replica indices with the add_replica method. To inherit the settings from the primary index, add inherit:true.

Ruby

class Book < ActiveRecord::Base
  attr_protected

  include AlgoliaSearch

  algoliasearch(per_environment: true) do
    searchableAttributes [:name, :author, :editor]

    # Define a replica index to search by `author` only
    add_replica("Book_by_author", per_environment: true) do
      searchableAttributes [:author]
    end

    # define a replica index with custom ordering but same settings than the main block
    add_replica("Book_custom_order", inherit: true, per_environment: true) do
      customRanking ["asc(rank)"]
    end
  end

end

Share a single index

If you want to share an index for multiple models, make sure that your object IDs are unique. For example, you can prepend the model class name to the record’s ID:

Ruby

class Student < ActiveRecord::Base
  attr_protected

  include AlgoliaSearch

  algoliasearch(index_name: "people", id: :algolia_id) do
    # [...]
  end

  private
  def algolia_id
    # ensure the teacher & student IDs are not conflicting
    "student_#{id}"
  end
end

class Teacher < ActiveRecord::Base
  attr_protected

  include AlgoliaSearch

  algoliasearch(index_name: "people", id: :algolia_id) do
    # [...]
  end

  private
  def algolia_id
    # ensure the teacher & student IDs are not conflicting
    "teacher_#{id}"
  end
end

To reindex a model that’s part of a shared index, you must use Model.reindex! instead of Model.reindex. If you use reindex, the resulting index would only contain records for the current model. For more information, see Zero-downtime indexing

Target multiple indices

To index records in several indices, use the add_index method.

Ruby

class Book < ActiveRecord::Base
  attr_protected

  include AlgoliaSearch

  PUBLIC_INDEX_NAME = "Book_#{Rails.env}"
  SECURED_INDEX_NAME = "SecuredBook_#{Rails.env}"

  # store all books in index 'SECURED_INDEX_NAME'
  algoliasearch(index_name: SECURED_INDEX_NAME) do
    searchableAttributes [:name, :author]
    # convert security to tags
    tags do
      [released ? "public" : "private", premium ? "premium" : "standard"]
    end

    # store all 'public' (released and not premium) books in index 'PUBLIC_INDEX_NAME'
    add_index(PUBLIC_INDEX_NAME, if: :public?) do
      searchableAttributes [:name, :author]
    end
  end

  private
  def public?
    released && !premium
  end

end