The Redis SCAN command allows you to iterate over the key space. On a single Redis node you can SCAN all keys or just keys matching a pattern. It’s a slow operation: O(N) where N is the number of keys in the database. However, it can be useful when you want to view every item in the database or when there’s no way to find your values without traversing everything. Due to the way that Redis shards data though, it may be difficult to SCAN keys on a Redis Cluster. It is possible but it takes a little more work.