To learn about how to set cache data expiration time, see the following description on the official Memcached website:
An expiration time, in seconds, can be up to 30 days. After 30 days, it is treated as a unix timestamp of an exact date.
That is, 0 - 2592000 indicates the time length from the current time (in seconds, with a maximum of 2592000 seconds, i.e., 30 days). If it is greater than 2592000, it is treated as a UNIX time stamp.
If this value is set at 0, the data does not expire, but may still become invalid because of factors such as data eviction.
|0||If this value is set at 0, the data does not expire, but may still become invalid because of factors such as data eviction.|
|<=2592000 seconds (30 days)||The relative time starting from the current time point.|
|>2592000||The absolute time starting from 00:00:00 on January 1, 1970.|