library/Rediska/Zend/Cache/Backend/Redis.php
public function getIdsNotMatchingTags($tags = array())
    {
            $sets = $this->_preprocessTagIds($tags);
            array_unshift($sets, $this->_options['storage']['set_ids']);
            $data = $this->getRediska()->diffSets($sets);
            return $data;
    }
public function getIdsNotMatchingTags($tags = array())
    {
            $sets = $this->_preprocessTagIds($tags);
            array_unshift($sets, $this->_options['storage']['set_ids']);
            $data = $this->getRediska()->diffSets($sets);
            return $data;
    }
Return an array of stored cache ids which don't match given tags

In case of multiple tags, a logical OR is made between tags

@param array $tags array of tags
@return array array of not matching cache ids (string)