Don't pluck project IDs for events

By instead using a sub-query we save ourselves the overhead of loading
any data into memory only to pass it on to another query.

2 files changed, 7 insertions, 1 deletions

diff --git a/app/models/event.rb b/app/models/event.rb
index 01d008035a5..8dfc1d04709 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -47,7 +47,11 @@ class Event < ActiveRecord::Base
   # Scopes
   scope :recent, -> { reorder(id: :desc) }
   scope :code_push, -> { where(action: PUSHED) }
-  scope :in_projects, ->(project_ids) { where(project_id: project_ids).recent }
+
+  scope :in_projects, ->(projects) do
+    where(project_id: projects.reorder(nil).id_only).recent
+  end
+
   scope :with_associations, -> { includes(project: :namespace) }
   scope :for_milestone_id, ->(milestone_id) { where(target_type: "Milestone", target_id: milestone_id) }
 
diff --git a/app/models/project.rb b/app/models/project.rb
index 4bd51449c25..63ecf5b7105 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -215,6 +215,8 @@ class Project < ActiveRecord::Base
   scope :public_and_internal_only, -> { where(visibility_level: Project.public_and_internal_levels) }
   scope :non_archived, -> { where(archived: false) }
 
+  scope :id_only, -> { select(:id) }
+
   state_machine :import_status, initial: :none do
     event :import_start do
       transition [:none, :finished] => :started