Setting the time-to-live (TTL) for value
Use the USING TTL N
option with INSERT and UPDATE
statements to automatically expire data in a column.
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';