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:
```
slow_query_log = 1
slow_query_log_file = /var/log/mysql/slow.log
log_slow_query_time = 2
```
For older versions use long_query_time instead of log_slow_query_time

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.
November 11, 2018