library/Rediska/Zend/Cache/Backend/Redis.php
public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
    {
        if( $tags && ! is_array($tags)) {
            $tags = array($tags);
        }
        $result = true;
        switch ($mode) {
            case Zend_Cache::CLEANING_MODE_ALL:
                $this->_removeIds($this->getIds());
                break;

            case Zend_Cache::CLEANING_MODE_OLD:
                break;

            case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
                $this->_removeIdsByMatchingTags($tags);
                break;

            case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
                $this->_removeIdsByNotMatchingTags($tags);
                break;

            case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
                $this->_removeIdsByMatchingAnyTags($tags);
                break;

            default:
                Zend_Cache::throwException('Invalid mode for clean() method: '.$mode);
        }
        return $this->_collectGarbage();
    }
public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
    {
        if( $tags && ! is_array($tags)) {
            $tags = array($tags);
        }
        $result = true;
        switch ($mode) {
            case Zend_Cache::CLEANING_MODE_ALL:
                $this->_removeIds($this->getIds());
                break;

            case Zend_Cache::CLEANING_MODE_OLD:
                break;

            case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
                $this->_removeIdsByMatchingTags($tags);
                break;

            case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
                $this->_removeIdsByNotMatchingTags($tags);
                break;

            case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
                $this->_removeIdsByMatchingAnyTags($tags);
                break;

            default:
                Zend_Cache::throwException('Invalid mode for clean() method: '.$mode);
        }
        return $this->_collectGarbage();
    }
Clean some cache records

Available modes are :
'all' (default)  => remove all cache entries ($tags is not used)
'old'            => supported
'matchingTag'    => supported
'notMatchingTag' => supported
'matchingAnyTag' => supported

@param  string $mode Clean mode
@param  array  $tags Array of tags
@throws Zend_Cache_Exception
@return boolean True if no problem