TTL
The TTL
command in DiceDB is used to retrieve the remaining time to live (TTL) of a key that has an expiration set. The TTL is returned in seconds. This command is useful for understanding how much longer a key will exist before it is automatically deleted by DiceDB.
Syntax
Parameters
Parameter | Description | Type | Required |
---|---|---|---|
key | The key for which you want to check the TTL. | String | Yes |
Return values
Condition | Return Value |
---|---|
The remaining TTL in seconds | A positive integer |
The key exists but has no associated expiration time | -1 |
The key does not exist. | -2 |
Behaviour
- If the
key
exists and has an expiration time set, the command returns the remaining time to live in seconds. - If the
key
exists but does not have an expiration time set, the command returns-1
. - If the
key
does not exist, the command returns-2
.
Errors
Wrong number of arguments
:- Error Message:
(error) ERR wrong number of arguments for 'ttl' command
- Occurs when attempting to use the command with incorrect number of arguments
- Error Message:
Example Usage
Check TTL for key with expiration
In this example, a key mykey
is created with a value “Hello”. Then, an expiration time of 10 seconds is set using the EXPIRE
command. When TTL
is called on mykey
, it returns 10, indicating that the key will expire in 10 seconds.
Check TTL for key without expiration
In this example, the key mykey
is set with a value of “Hello” but no expiration is set. The TTL
command returns -1
, indicating that the key exists but has no associated expiration.
Check TTL for non-existent key
In this example, the key non_existent_key
does not exist in the DiceDB database. The TTL
command returns -2
, indicating that the key does not exist.
Invalid usage
In this example, the TTL
command is used with an extra argument. This results in an error, as the TTL
command accepts only one argument.
Best Practices
Alternatives
PTTL
: Similar toTTL
but returns the time-to-live in milliseconds instead of seconds