HKEYS
Syntax
1. HKEYS key
Time complexity: O(N) where N is the size of the hash.
ACL categories: @read, @hash, @slow
Returns all field names in the hash stored at key.
Return
Array reply: list of fields in the hash, or an empty list when key does not exist.
Examples
1. dragonfly> HSET myhash field1 "Hello"
2. (integer) 1
3. dragonfly> HSET myhash field2 "World"
4. (integer) 1
5. dragonfly> HKEYS myhash
6. 1) "field1"
7. 2) "field2"
