mysql regularly deletes expired data records

1. After connecting and logging in to MySQL, first check whether MySQL has enabled the event function:

命令：show variables like '%sc%';

It is found that event_sheduler is OFF;

2. Open event_scheuler:

• Temporarily open (after the mysql service is restarted, it will fail)
• SET GLOBAL event_scheduler = ON;

SET GLOBAL event_scheduler = 1; — 0 means off

permanently on

Add the following to the [mysqld] section in my.cnf, and then restart mysql (mysql restart command: service mysqld restart)
event_scheduler=ON

3. Create an event. Here is an example to periodically delete data that is expired for 2 minutes in the wififlows table every 5 seconds :

create event e_delete_wififlows on schedule every 5 second do delete from wififlows where timestamp <  (CURRENT_TIMESTAMP() + INTERVAL -2 MINUTE);

If this event exists beforehand, it can be deleted with the following command:

drop event if exists e_delete_wififlows; 

Then use show events; to see the events that exist

4. Start the event:

alter event e_del_wififlows on completion preserve enable;

5. Close the event:

alter event e_del_wififlowa on completion preserve disable;