Redis store key without a value

Question

When using the Redis expire commands like SETEX and TTL, there are scenarios in which there is no need for the key to hold a v

Answer 1

Who said that you should actually store anything in redis key?

Empty string "" is a perfectly valid value for a redis key, and it's a shortest possible one:

> SET foo ""
OK
> GET foo
""
> BITCOUNT foo
(integer) 0

Answer 2

I would avoid using "". How about simple 0 ?

127.0.0.1:6379> set akey 0
OK
127.0.0.1:6379> memory usage akey
(integer) 48
127.0.0.1:6379> set akey ""
OK
127.0.0.1:6379> memory usage akey
(integer) 50
127.0.0.1:6379>

Answer 3

Do you serialize everything coming to and from redis, yourself? If so, you may consider using a sentinel value (like a NONE constant, etc.) which is set to something like 'None'.

Answer 4

I would store one byte of data that could also be broadly interpreted as "truthy", such as the ASCII character 1.