1. Modify the MySQL config
sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf
sudo service mysql reload
slow_query_log = 1
slow_query_log_file = /var/log/mysql/mysql-slow.log
long_query_time = 2
log-queries-not-using-indexes
2. (Optional) Check the log path
sudo mysql -u root -p
mysql> SHOW GLOBAL VARIABLES LIKE 'slow_query_log%';
+---------------------+-------------------------------+
| Variable_name | Value |
+---------------------+-------------------------------+
| slow_query_log | ON |
| slow_query_log_file | /var/log/mysql/mysql-slow.log |
+---------------------+-------------------------------+
2 rows in set (0.03 sec)
3. See the log
sudo tail -f /var/log/mysql/mysql-slow.log
