安装完mysql数据库后的优化（删除多余用户和数据库）

1、查看数据库的版本信息：

MariaDB [(none)]> select version();+----------------+| version()      |+----------------+| 5.5.52-MariaDB |+----------------+1 row in set (0.18 sec)

2、删除多余的账号（除root和localhost的）

MariaDB [(none)]> use mysqlMariaDB [mysql]> select user,host from mysql.user;+------+------------------------+| user | host                   |+------+------------------------+| root | 127.0.0.1              || root | ::1                    ||      | localhost              || root | localhost              ||      | lvs-dr01.saltstack.com || root | lvs-dr01.saltstack.com |+------+------------------------+6 rows in set (0.03 sec)MariaDB [mysql]> delete from mysql.user where (user,host) not in (select 'root','localhost');Query OK, 5 rows affected (0.05 sec)MariaDB [mysql]> select user,host from mysql.user;+------+-----------+| user | host      |+------+-----------+| root | localhost |+------+-----------+1 row in set (0.05 sec)

3、修改mysql默认的mysql管理账号

修改默认的mysql管理账号（root改为mysql，并设置新密码为redhat12345）

MariaDB [mysql]> update user set user="admin" where user="root";MariaDB [mysql]> update mysql.user set user='admin',password=password('redhat12345');Query OK, 1 row affected (0.08 sec)Rows matched: 1  Changed: 1  Warnings: 0MariaDB [mysql]> flush privileges;Query OK, 0 rows affected (0.03 sec)[root@LVS-DR01 ~]# mysql -uadmin -p'redhat12345'MariaDB [(none)]> user mysql；MariaDB [mysql]> show tables;

继续查询：

MariaDB [mysql]> select user,host from mysql.user;+-------+-----------+| user  | host      |+-------+-----------+| admin | localhost |+-------+-----------+1 row in set (0.00 sec)

4、删除test数据库：

MariaDB [mysql]> drop database test;MariaDB [mysql]> flush privileges;MariaDB [(none)]> show databases;+--------------------+| Database           |+--------------------+| information_schema || mysql              || performance_schema |+--------------------+3 rows in set (0.06 sec)

5、优化权限字典表mysql.db

如下所示：新建MySQL数据库后，默认创建的test数据库权限比较怪异，所有可连接的用户都能够拥有权限访问该库，并操作其中的对象，Host为%，User为空，说明了不受限制，所有能连接到MySQL的用户，全部拥有test及test开头的数据库的几乎所有权限。

MariaDB [mysql]> select * from mysql.db where db like 'test%' \G*************************** 1. row ***************************                 Host: %                   Db: test                 User:           Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: N      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: N         Execute_priv: N           Event_priv: Y         Trigger_priv: Y*************************** 2. row ***************************                 Host: %                   Db: test\_%                 User:           Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: N      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: N         Execute_priv: N           Event_priv: Y         Trigger_priv: Y2 rows in set (0.31 sec)优化的操作：MariaDB [mysql]> truncate table mysql.db;Query OK, 0 rows affected (0.01 sec)MariaDB [mysql]> select * from mysql.db where db like 'test%' \GEmpty set (0.00 sec)

6、如何优化/root/.mysql_history文件

[root@LVS-DR01 ~]# tail -20 ~/.mysql_history flush privileges;select user,host from mysql.user;delete from mysql.user where user="'molewan1'@'10.10.10.%'";delete from mysql.db where user='molewan1'@'10.10.10.%';select user,host from mysql.user;delete from mysql.user where user=molewan1;delete from mysql.user where user='molewan1@10.10.10.%';flush privileges;select user,host from mysql.user;delete from mysql.user where user="molewan1" and host ="10.10.10.%";flush privileges;select user,host from mysql.user;delete from mysql.user where user="molewan" and host="10.10.10.%";flush privileges;create user molewan@'10.10.10.%' identified by 'molewan';select user,host from mysql.user;desc mysql.user;update mysql.user set password=password('admin') where user='admin' and host='localhost';flush privileges;\q

说明：在Linux/Unix系统下，使用mysql命令行工具执行的所有操作，都会被记录到一个名为.mysql_history的文件中，该文件默认保存在当前用户的根目录下

这个设定原本是为了提升mysql命令行操作体验，在mysql中操作命令就可以上下翻动了，但某些情况下缺会造成隐患。

如何消除隐患：

方法1：基于DB层的操作修改MYSQL_HISTFILE环境变量，将其值改为/dev/null，这样所有的操作都会被输出到空，操作的历史自然不会被保留。方法2：基于系统层操作仍旧保留这个文件，但是改文件实际上未/dev/null的软链接，这样所有的操作都会被输出到空，操作的历史自然不会被保留。ln -f -s /dev/null ~/.mysql_history[root@LVS-DR01 ~]# tail -20 ~/.mysql_history 这时候就没有输出了

到此，安装完成后的基本优化已经完成