How to Enable MariaDB Slow Query Log and Change the Long Query Time on CentOS 7.6

How To Enable the Slow Query log, Change the Long Query time for MariaDB database On CentOS 7.6

Procedure

Login to the MariaDB database using the root password as follows

[root@linuxhelp ~]# mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 5.5.60-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> SET GLOBAL slow_query_log='ON';
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SET GLOBAL long_query_time=6;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> exit
Bye

After enabling the Slow query log and setting the long query time,navigate to the file location of the slow query log

[root@linuxhelp ~]# cd /var/lib/mysql

List the directories in the mysql directory to check the slow query log

[root@linuxhelp mysql]# ls -la
total 28708
drwxr-xr-x   4 mysql mysql      191 Aug  3 10:18 .
drwxr-xr-x. 65 root  root      4096 Apr 15 11:09 ..
-rw-rw----   1 mysql mysql    16384 Aug  3 10:08 aria_log.00000001
-rw-rw----   1 mysql mysql       52 Aug  3 10:08 aria_log_control
-rw-rw----   1 mysql mysql 18874368 Aug  3 10:08 ibdata1
-rw-rw----   1 mysql mysql  5242880 Aug  3 10:09 ib_logfile0
-rw-rw----   1 mysql mysql  5242880 Apr 15 10:44 ib_logfile1
-rw-rw----   1 mysql mysql      176 Aug  3 10:18 linuxhelp-slow.log
drwx------   2 mysql mysql     4096 Apr 15 10:44 mysql
srwxrwxrwx   1 mysql mysql        0 Aug  3 10:09 mysql.sock
drwx------   2 mysql mysql     4096 Apr 15 10:44 performance_schema

Login to the MariaDB database to disable the slow query log as follows

 
[root@linuxhelp mysql]# mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 5
Server version: 5.5.60-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> SET GLOBAL slow_query_log = 'OFF';
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> exit
Bye

With this, Slow query log has been successfully enabled , set the time interval for the execution of the query and disabled it successfully for MariaDB On CentOS 7.6