Add index on ci_runners.contacted_at

changelogs/unreleased/add_index_on_ci_runners_contacted_at.yml

+---
+title: Add index on ci_runners.contacted_at
+merge_request: 10876
+author: blackst0ne

db/migrate/20170426181740_add_index_on_ci_runners_contacted_at.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddIndexOnCiRunnersContactedAt < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_runners, :contacted_at
+  end
+
+  def down
+    remove_concurrent_index :ci_runners, :contacted_at if index_exists?(:ci_runners, :contacted_at)
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170426175636) do
+ActiveRecord::Schema.define(version: 20170426181740) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -296,6 +296,7 @@ ActiveRecord::Schema.define(version: 20170426175636) do
     t.boolean "locked", default: false, null: false
   end
 
+  add_index "ci_runners", ["contacted_at"], name: "index_ci_runners_on_contacted_at", using: :btree
   add_index "ci_runners", ["is_shared"], name: "index_ci_runners_on_is_shared", using: :btree
   add_index "ci_runners", ["locked"], name: "index_ci_runners_on_locked", using: :btree
   add_index "ci_runners", ["token"], name: "index_ci_runners_on_token", using: :btree