function bump($user_id = 0)
	{
		global $db, $user;

		$current_time = time();
		if ($user_id == 0)
			$user_id = $user->data['user_id'];

		$db->sql_transaction('begin');

		$sql = 'UPDATE ' . POSTS_TABLE . "
		SET post_time = $current_time
		WHERE post_id = {$this->topic_last_post_id}
		AND topic_id = {$this->topic_id}";
		$db->sql_query($sql);

		$this->topic_bumped = 1;
		$this->topic_bumper = $user_id;
		$this->topic_last_post_time = $current_time;
		$sql = 'UPDATE ' . TOPICS_TABLE . "
		SET topic_last_post_time = $current_time,
		topic_bumped = 1,
		topic_bumper = $user_id
		WHERE topic_id = $topic_id";
		$db->sql_query($sql);

		update_post_information('forum', $this->forum_id);

		$sql = 'UPDATE ' . USERS_TABLE . "
		SET user_lastpost_time = $current_time
		WHERE user_id = $user_id";
		$db->sql_query($sql);

		$db->sql_transaction('commit');

		markread('post', $this->forum_id, $this->topic_id, $current_time, $user_id);

		add_log('mod', $this->forum_id, $this->topic_id, 'LOG_BUMP_TOPIC', $this->topic_title);
	}