Merge branch 'rp/reduce-n+1-queries-in-namespaces-api-1' into 'master'

Include route and hosted_plan to reduce n+1 queries in namespaces list api

See merge request gitlab-org/gitlab!43846

app/models/namespace.rb

@@ -83,6 +83,7 @@ class Namespace < ApplicationRecord
 
   scope :for_user, -> { where('type IS NULL') }
   scope :sort_by_type, -> { order(Gitlab::Database.nulls_first_order(:type)) }
+  scope :include_route, -> { includes(:route) }
 
   scope :with_statistics, -> do
     joins('LEFT JOIN project_statistics ps ON ps.namespace_id = namespaces.id')

ee/app/models/ee/namespace.rb

@@ -36,6 +36,7 @@ module EE
       accepts_nested_attributes_for :namespace_limit
 
       scope :include_gitlab_subscription, -> { includes(:gitlab_subscription) }
+      scope :include_gitlab_subscription_with_hosted_plan, -> { includes(gitlab_subscription: :hosted_plan) }
       scope :join_gitlab_subscription, -> { joins("LEFT OUTER JOIN gitlab_subscriptions ON gitlab_subscriptions.namespace_id=namespaces.id") }
 
       scope :eligible_for_trial, -> do

ee/spec/requests/api/namespaces_spec.rb

@@ -138,7 +138,7 @@ RSpec.describe API::Namespaces do
         #   an association on group, not namespace).
         # The route adds one for each namespace.
         # And more...
-        expect { get api("/namespaces", user) }.not_to exceed_all_query_limit(control).with_threshold(10)
+        expect { get api("/namespaces", user) }.not_to exceed_all_query_limit(control).with_threshold(7)
       end
 
       it 'includes max_seats_used' do

lib/api/namespaces.rb

@@ -32,7 +32,9 @@ module API
       get do
         namespaces = current_user.admin ? Namespace.all : current_user.namespaces
 
-        namespaces = namespaces.include_gitlab_subscription if Gitlab.ee?
+        namespaces = namespaces.include_route
+
+        namespaces = namespaces.include_gitlab_subscription_with_hosted_plan if Gitlab.ee?
 
         namespaces = namespaces.search(params[:search]) if params[:search].present?