Indexing of JSONB embedded Ecto2 models in Postgres 9.4+ - postgresql

Question

I'm not clear on how to index embedded structs stored as JSONB with Ecto2/Postgres 9.4+
I have a schema with two embedded structs using embeds_one and embeds_many. They are ecto :map fields represented in Postgres as JSONB. I am wondering how I can be sure they are indexed (using Gin?) for speedy queries? I am not sure if this happens automagically, if I need to add an index to my migration or if I need to do it manually using psql etc..
Just looking for clarification on how this works.
Thanks!
defmodule App.Repo.Migrations.CreateClient
def change do
create table(:clients) do
add :name, :string
add :settings, :map
add :roles, {:array, :map}, default: []
timestamps()
end
// This works for normal schema/model fields
create index(:clients, [:name], unique: true, using: :gin)
// BUT CAN I INDEX MY EMBEDS HERE?
// GUESS:
create index(:clients, [:settings], using: :gin)
end
end
defmodule App.Client do
schema "client" do
field :name, :string
embeds_one :settings, Settings // single fixed schema "Settings" model
embeds_many :roles, Role // array of "Role" models
end
end
defmodule Settings do
use Ecto.Model
embedded_schema do // ALSO
field :name, :string // are types relevant?
field :x_count, :integer // stored as strings (INDEXED?)
field :is_active, :boolean // deserialized via cast?
end
end
defmodule Role do
use Ecto.Model
embedded_schema do
field :token
field :display_english
field :display_spanish
end
end

Answer 1

I think you just need to add this:
create index(:clients, [:name], unique: true, using: :gin)
to your migration file.
Or if the index sql statement is gonna be complicated, you could do it with execute so it would be something like this:
execute("CREATE INDEX clients_name_index ON clients USING GIN (name)")
I have not tested it but I believe it should work.