Returns the number of existing keys out of those specified after updating the time they were last accessed.
TOUCH
key [key…]
Alters the last access time of a key(s). A key is ignored if it does not exist.
Integer reply: the number of touched keys.
O(N) where N is the number of keys that will be touched.
@fast @keyspace @read
127.0.0.1:6379> SET key1 "Hello"
OK
127.0.0.1:6379> SET key2 "World"
OK
127.0.0.1:6379> TOUCH key1 key2
(integer) 2
COPY, DEL, DUMP, EXISTS, EXPIRE, EXPIREAT, EXPIRETIME, KEYS, MIGRATE, MOVE, OBJECT, OBJECT ENCODING, OBJECT FREQ, OBJECT HELP, OBJECT IDLETIME, OBJECT REFCOUNT, PERSIST, PEXPIRE, PEXPIREAT, PEXPIRETIME, PTTL, RANDOMKEY, RENAME, RENAMENX, RESTORE, SCAN, SORT, SORT_RO, TTL, TYPE, UNLINK, WAIT, WAITAOF.