TOUCHCount how many of the given keys exist.
| 構文 | TOUCH key [key ...] |
| グループ | generic |
| 引数の数 | -2 |
| 導入バージョン | 1.0.0 |
| フラグ | readonly |
| 計算量 | O(N) keys — one existence probe per key on its owning shard |
| Redis 互換性 | differs: kevy has no idle-time clock to reset, so TOUCH is EXISTS with the eviction bookkeeping the probe already does |