RANDOMKEYReturn a random key from the keyspace.
| 语法 | RANDOMKEY |
| 分组 | scan |
| 参数个数 | 1 |
| 起始版本 | 1.0.0 |
| 标志 | readonly |
| 复杂度 | O(1) expected — each shard probes a random slot, and the origin folds the candidates through a reservoir weighted by shard key counts, so every key is equally likely |
| Redis 兼容性 | full |