“Apache Cassandra a Time to Live or TTL value for the data in a given column. You can use the TTL value in an INSERT or UPDATE statement allowing the data in that column to expire after the duration is elapsed.”
In this post, we will discuss how you can set and get the TTL value of a given column using the INSERT statement and TTL function, respectively.
Cassandra Create Column With TTL Value
The following queries create a keyspace and a new table to hold the target data.
create keyspace zero_day
with replication = {
'class': 'SimpleStrategy',
'replication_factor': 1
};
use zero_day;
create table records(
id int,
cve_number text,
report_date date,
affected_vendor text,
severity float,
primary key(id)
);
We can then insert data with TTL values as shown in the queries below:
insert into records(id, cve_number, report_date, affected_vendor, severity)
values (1, 'CVE-2021-33852', '2022-12-02', 'WordPress', 6.0) using ttl 120;
insert into records(id, cve_number, report_date, affected_vendor, severity)
values (2, 'CVE-2020-14723', '2020-01-11', 'Oracle', 8.2) using ttl 180;
insert into records(id, cve_number, report_date, affected_vendor, severity)
values (3, 'CVE-2019-19306', '2019-10-14', 'Zoho', 5.4) using ttl 240;
insert into records(id, cve_number, report_date, affected_vendor, severity)
values (4, 'CVE-2021-33850', '2021-10-18', 'Microsoft', 5.0) using ttl 300;
insert into records(id, cve_number, report_date, affected_vendor, severity)
values (5, 'CVE-2020-24600', '2020-07-01', 'Shilpi', 8.6) using ttl 360;
apply batch;
The insert statements add data with TTL values to the specified table. Keep in mind that the TTL value is defined in seconds.
Cassandra Show TTL Values
To show the TTL value of a given column, use the TTL function as shown in the example below:
The query above should display the remaining TTL value for the row with id of 5.
An example output is as shown:
-----------------+-----
ttl(cve_number) | 169
(1 rows)
Once the TTL value is elapsed, the data is removed from the table as shown:
The row does not exist in this case as the data has been removed.
-----------------
(0 rows)
Conclusion
In this tutorial, we discussed how to set and get the TTL value of a given row in Cassandra.
Thanks for reading!!
