Enable Slow Query Logging

Enable Slow Query Logging

slow_query_log=1
slow_query_log_file=/var/log/mysql/mysql.slow 
long_query_time=1

enable on the fly

SET GLOBAL slow_query_log = 'ON';
SET GLOBAL long_query_time = 1;
SET GLOBAL slow_query_log_file = '/var/log/mysql/mysql.slow';

to test it out

# log out of mysql / log back in (this reloads the session variables)
SELECT SLEEP(2);
SET GLOBAL slow_query_log = 'OFF';

to query if it’s on

mysql -e 'select @@slow_query_log;'