Generating a lot of data in the slow query log makes it more difficult to work with as it grows larger. It is important to rotate the log regularly to ensure it does not grow too large to work with. This can be accomplished with a cron job, but it can be done in MySQL directly using the event scheduler.
SET GLOBAL event_scheduler=ON;
DROP EVENT if exists rotate_slow_log_event;
CREATE DEFINER=root@localhost EVENT rotate_slow_log_event
EVERY 1 HOUR
ON COMPLETION PRESERVE
COMMENT 'Rotate slow query log hourly'
set global slow_query_log_file=CONCAT('slow-', unix_timestamp(), '.log');