First enable the MySQL slow query log in the MySQL configuration file my.cnf

CentOS/RHEL Based
[cc lang=”bash”]vi /etc/my.cnf[/cc]

Debian/Ubuntu Based
[cc lang=”bash”]vi /etc/mysql/my.cnf[/cc]

Add the records below at the end of the [mysqld] section:
[cc lang=”bash”]slow_query_log = 1
log-slow-queries = /var/log/mysql-slow.log
long_query_time = 1[/cc]

Create slow log file

[cc lang=”bash”]# touch /var/log/mysql-slow.log
# chown mysql:mysql /var/log/mysql-slow.log[/cc]

Restart MySQL service

CentOS/RHEL
[cc lang=”bash”]service mysqld restart[/cc]

Debian/Ubuntu
[cc lang=”bash”]service mysql restart[/cc]

If MariaDB installed
[cc lang=”bash”]service mariadb restart[/cc]

Tail the slow log file
[cc lang=”bash”]tail -f /var/log/mysql-slow.log[/cc]