src/M6Web/Component/Redis/Cache.php
public function keys($pattern)
    {
        $pattern = $this->getPatternKey().$pattern;

        return $this->runOnAllRedisServer(
            function ($redis) use ($pattern) {
                $this->notifyEvent('keys', array($pattern));

                return $redis->keys($pattern);
            }
        );
    }
public function keys($pattern)
    {
        $pattern = $this->getPatternKey().$pattern;

        return $this->runOnAllRedisServer(
            function ($redis) use ($pattern) {
                $this->notifyEvent('keys', array($pattern));

                return $redis->keys($pattern);
            }
        );
    }
return an array of server with all the keys stored in the cache according to $pattern
use only for debug

@param string $pattern the pattern - ie : raoul*

@return array