run_without_lock

# File activerecord/lib/active_record/migration.rb, line 1266
      def run_without_lock
        migration = migrations.detect { |m| m.version == @target_version }
        raise UnknownMigrationVersionError.new(@target_version) if migration.nil?
        result = execute_migration_in_transaction(migration, @direction)

        record_environment
        result
      end