Tag: mysqldumpslow

  • How to enable slow query log in MySQL/MariaDB

    To enable MySQL slow query login, edit my.cnf file

    vi /etc/my.cnf
    

    For MariaDB, edit

    vi /etc/mysql/mariadb.conf.d/50-server.cnf
    

    Add

    long_query_time = 2
    slow_query_log = 1
    slow_query_log_file = /var/log/mysql/mysql_slow.log
    

    Restart MySQL

    systemctl restart mysql
    

    On CentOS, the command is “systemctl retstart mysqld”. If you are using MariaDB, use “systemctl restart mariadb”.

    You can use mysqldumpslow command to view slow queries.

    mysqldumpslow /var/log/mysql/slow.log
    

    To test, you can run the command

    SELECT SLEEP(10);
    

    This will simulate a query, that take 10 seconds.