library/Rediska/Zend/Cache/Backend/Redis.php
public function touch($id, $extraLifetime)
    {
        $data = $this->getRediska()->getFromHash(
            $this->_options['storage']['prefix_key'].$id, array(self::FIELD_INF)
        );
        $lifetime = $this->getRediska()
            ->getLifetime($this->_options['storage']['prefix_key'] . $id);
        if ($data[self::FIELD_INF] === 0) {
            $expireAt = time() + $lifetime + $extraLifetime;
            return (bool) $this->getRediska()->expire(
                $this->_options['storage']['prefix_key'].$id, $expireAt, true
            );
        }
        return false;
    }
public function touch($id, $extraLifetime)
    {
        $data = $this->getRediska()->getFromHash(
            $this->_options['storage']['prefix_key'].$id, array(self::FIELD_INF)
        );
        $lifetime = $this->getRediska()
            ->getLifetime($this->_options['storage']['prefix_key'] . $id);
        if ($data[self::FIELD_INF] === 0) {
            $expireAt = time() + $lifetime + $extraLifetime;
            return (bool) $this->getRediska()->expire(
                $this->_options['storage']['prefix_key'].$id, $expireAt, true
            );
        }
        return false;
    }
Give (if possible) an extra lifetime to the given cache id

@param string $id cache id
@param int $extraLifetime
@return boolean true if ok