public function failure( $job, Exception $exception ) {
		$insert = $this->database->insert( $this->failures_table, array(
			'job'       => serialize( $job ),
			'error'     => $this->format_exception( $exception ),
			'failed_at' => $this->datetime(),
		) );

		if ( $insert ) {
			$this->delete( $job );

			return true;
		}

		return false;
	}