Remove old project_id index and make sure mysql work

db/migrate/20170622135728_add_unique_constraint_to_ci_variables.rb

@@ -6,18 +6,28 @@ class AddUniqueConstraintToCiVariables < ActiveRecord::Migration
   disable_ddl_transaction!
 
   def up
-    unless index_exists?(:ci_variables, columns)
-      add_concurrent_index(:ci_variables, columns, unique: true)
+    unless this_index_exists?
+      add_concurrent_index(:ci_variables, columns, name: index_name, unique: true)
     end
   end
 
   def down
-    if index_exists?(:ci_variables, columns) && Gitlab::Database.postgresql?
-      remove_concurrent_index(:ci_variables, columns)
+    if this_index_exists? && Gitlab::Database.postgresql?
+      remove_concurrent_index(:ci_variables, columns, name: index_name)
     end
   end
 
+  private
+
+  def this_index_exists?
+    index_exists?(:ci_variables, name: index_name)
+  end
+
   def columns
     @columns ||= [:project_id, :key, :environment_scope]
   end
+
+  def index_name
+    'index_ci_variables_on_project_id_and_key_and_environment_scope'
+  end
 end

db/migrate/20170623080805_remove_ci_variables_project_id_index.rb

+class RemoveCiVariablesProjectIdIndex < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    if index_exists?(:ci_variables, :project_id)
+      remove_concurrent_index(:ci_variables, :project_id)
+    end
+  end
+
+  def down
+    unless index_exists?(:ci_variables, :project_id)
+      add_concurrent_index(:ci_variables, :project_id)
+    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: 20170622135728) do
+ActiveRecord::Schema.define(version: 20170623080805) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"