Determining time-to-live (TTL) for a column

How to insert and retrieve data pertaining to TTL for columns.

To set the TTL for data, use the USING TTL keywords. The TTL function may be used to retrieve the TTL information.

The USING TTL keywords can be used to insert data into a table for a specific duration of time. To determine the current time-to-live for a record, use the TTL function.

Procedure

  • Insert data into the table cycling.calendar and use the USING TTL clause to set the expiration period to 86400 seconds.
    INSERT INTO cycling.calendar (race_id, race_name, race_start_date, race_end_date) VALUES (200, 'placeholder','2015-05-27', '2015-05-27') USING TTL 86400;
  • Issue a SELECT statement to determine how much longer the data has to live.
    SELECT TTL (race_name) from cycling.calendar WHERE race_id = 200;


    If you repeat this step after some time, the time-to-live value will decrease.

  • The time-to-live value can also be updated with the USING TTL keywords in an UPDATE command.
    UPDATE cycling.calendar USING TTL 300 SET race_name = 'dummy' WHERE race_id = 200 AND race_start_date = '2015-05-27' AND race_end_date = '2015-05-27';