Time to Live, also known as TTL, is the time until an item expires in Couchbase Server. By default, all items will have a TTL of 0, which indicates the item will be kept indefinitely. Typically when you add, set, or replace information, you would establish a custom TTL by passing it as a parameter to your method call. As part of normal maintenance operations, Couchbase Server will periodically remove all items with expirations that have passed.
Here is how to specify a TTL:
Values less than 30 days: if you want an item to live for less than 30 days, you can provide a TTL in seconds, or as Unix epoch time. The maximum number of seconds you can specify are the seconds in a month, namely 30 x 24 x 60 x 60. Couchbase Server will remove the item the given number of seconds after it stores the item.
Be aware that even if you specify a TTL as a relative value such as seconds into the future, it is actually stored in Couchbase server as an absolute Unix timestamp. This means, for example, if you store an item with a two-day relative TTL, immediately make a backup, and then restore from that backup three days later, the expiration will have passed and the data is no longer there.
Values over 30 days: if you want an item to live for more than 30 day you must provide a TTL in Unix epoch time; for instance, 1 095 379 198 indicates the seconds since 1970.
Note that Couchbase Server does lazy expiration, that is, expired items are flagged as deleted rather than being immediately erased. Couchbase Server has a maintenance process that will periodically look through all information and erase expired items. This maintenance process will run every 60 minutes, but it can be configured to run at a different interval. Couchbase Server will immediately remove an item flagged for deletion the next time the item requested; the server will respond that the item does not exist to the requesting process.
For more information about setting intervals for the maintenance
process, refer to the Couchbase Manual on