MySQL installation and simple tuning

Installation and tuning MySQL

1. Installation Precautions

• ubuntu18 installation

sudo apt-get update
sudo apt-get install -y mysql-server mysql-client
sudo mysql_secure_installation
sudo systemctl status mysql.service
sudo systemctl enable mysql.service

When performing mysql_secure_installation script:

Securing the MySQL server deployment.

Connecting to MySQL using a blank password.

VALIDATE PASSWORD PLUGIN can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD plugin?

Press y|Y for Yes, any other key for No: y

There are three levels of password validation policy:

LOW    Length >= 8
MEDIUM Length >= 8, numeric, mixed case, and special characters
STRONG Length >= 8, numeric, mixed case, special characters and dictionary file

Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2 <---这里一定要选择“2”，否则不使用sudo访问MySQL（$ mysql -uroot -p）将失败！
Please set the password for root here.

New password: 

Re-enter new password: 

Estimated strength of the password: 100 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.


Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.


Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
 - Dropping test database...
Success.

 - Removing privileges on test database...
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

All done! 

• Optional on MySQL permissions:

mysql> use mysql;
mysql> select User,Host,plugin from user;
+------------------+-----------+-----------------------+
| User             | Host      | plugin                |
+------------------+-----------+-----------------------+
| root             | localhost | auth_socket <--这里   |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| debian-sys-maint | localhost | mysql_native_password |
+------------------+-----------+-----------------------+

mysql> update user set plugin='mysql_native_password' where User='root' and Host='localhost';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost';
mysql> flush privileges;

• Modify the character set is UTF-8

mysql> show variables like 'char%';
mysql> show variables like 'collation%';

sudo vim /etc/mysql/conf.d/mysql.cnf
[mysql]
default-character-set = utf8

sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf
[mysqld]
collation-server = utf8_general_ci
character-set-server = utf8

sudo systemctl restart mysql.service

• View the running status

sudo systemctl status mysql.service
sudo lsof -i:3306
netstat -ntpl | grep 3306 | grep -v grep

mysql> show full processlist

2. Optimize Precautions

• Tuning MySQL script
  using the script tuning-primer.sh
  Download https://launchpad.net/mysql-tuning-primer/
  need to be copied to the same directory my.cnf tuning-primer.sh execution.
  Note, for the following error

FINAL LOGIN ATTEMPT FAILED - Unable to log into socket: /var/lib/mysql/mysql.sock

[Warning] Using a password on the command line interface can be insecure. mysqld is alive

You can solve the following configuration:

[client]
user = 用户名
password = 密码
socket = /var/lib/mysql/mysql.sock

After completion of tuning to delete the account password.

Note that the path tuning the script mysqladmin command of whether to get through.

• Other optimal allocation

skip-name-resolve
thread_cache_size = 256

Table analysis examples

mysql>   只看一条记录即可
explain SELECT count(new_cheat_id) FROM new_cheat WHERE account_id = '123456' AND offer_id = '111'\G

注意观察SQL扫描的总行数rows的值

show index from new_cheat;