Add unique index to subscriptions on subscribable and user and project

2 files changed, 19 insertions, 1 deletions

diff --git a/db/migrate/20161031181638_add_unique_index_to_subscriptions.rb b/db/migrate/20161031181638_add_unique_index_to_subscriptions.rb
new file mode 100644
index 00000000000..4b1b29e1265
--- /dev/null
+++ b/db/migrate/20161031181638_add_unique_index_to_subscriptions.rb
@@ -0,0 +1,18 @@
+class AddUniqueIndexToSubscriptions < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = true
+  DOWNTIME_REASON = 'This migration requires downtime because it changes a column to not accept null values.'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :subscriptions, [:subscribable_id, :subscribable_type, :user_id, :project_id], { unique: true, name: 'index_subscriptions_on_subscribable_and_user_id_and_project_id' }
+    remove_index :subscriptions, name: 'subscriptions_user_id_and_ref_fields' if index_name_exists?(:subscriptions, 'subscriptions_user_id_and_ref_fields', false)
+  end
+
+  def down
+    add_concurrent_index :subscriptions, [:subscribable_id, :subscribable_type, :user_id], { unique: true, name: 'subscriptions_user_id_and_ref_fields' }
+    remove_index :subscriptions, name: 'index_subscriptions_on_subscribable_and_user_id_and_project_id' if index_name_exists?(:subscriptions, 'index_subscriptions_on_subscribable_and_user_id_and_project_id', false)
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index fcdb5ab7dde..e3a4cf9b96d 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -1055,7 +1055,7 @@ ActiveRecord::Schema.define(version: 20161109150329) do
     t.integer "project_id"
   end
 
-  add_index "subscriptions", ["subscribable_id", "subscribable_type", "user_id"], name: "subscriptions_user_id_and_ref_fields", unique: true, using: :btree
+  add_index "subscriptions", ["subscribable_id", "subscribable_type", "user_id", "project_id"], name: "index_subscriptions_on_subscribable_and_user_id_and_project_id", unique: true, using: :btree
 
   create_table "taggings", force: :cascade do |t|
     t.integer "tag_id"