Add index for ci_runners if they are shared

db/migrate/20170121130655_add_index_to_ci_runners_for_is_shared.rb

+class AddIndexToCiRunnersForIsShared < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_runners, :is_shared
+  end
+
+  def down
+    if index_exists?(:ci_runners, :is_shared)
+      remove_index :ci_runners, :is_shared
+    end
+  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: 20170121123724) do
+ActiveRecord::Schema.define(version: 20170121130655) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -328,6 +328,7 @@ ActiveRecord::Schema.define(version: 20170121123724) do
     t.boolean "locked", default: false, null: false
   end
 
+  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