I think the docs are misleading. Looking at ``\DrupalDatabaseCache::clear()`` you can pass a string with ``wildcard = TRUE`` and the it will\

```php
db_delete($this->bin)
  ->condition('cid', db_like($cid) . '%', 'LIKE')
  ->execute();
```

Looking at memcache module, If I understand correctly ``\MemCacheDrupal::wildcards`` will do the same.