TTL key

Available since 1.0.0.

Time complexity: O(1)

Returns the remaining time to live of a key that has a timeout. This introspection capability allows a Redis client to check how many seconds a given key will continue to be part of the dataset.

In Redis 2.6 or older the command returns -1 if the key does not exist or if the key exist but has no associated expire.

Starting with Redis 2.8 the return value in case of error changed:

  • The command returns -2 if the key does not exist.
  • The command returns -1 if the key exists but has no associated expire.

See also the PTTL command that returns the same information with milliseconds resolution (Only available in Redis 2.6 or greater).

*Return value

Integer reply: TTL in seconds, or a negative value in order to signal an error (see the description above).

*Examples

redis> SET mykey "Hello" 

  1. "OK"

redis> EXPIRE mykey 10 

  1. (integer) 1

redis> TTL mykey 

  1. (integer) 10
redis>