查看插件：
mysql> show plugins;
mysql> select plugin_name,plugin_status,plugin_type,load_option,plugin_library from information_schema.plugins;默认插件目录：
mysql> show variables like 'plugin_dir';
+---------------+------------------------+
| Variable_name | Value |
+---------------+------------------------+
| plugin_dir | D:\mysql57\lib\plugin\ |
+---------------+------------------------+配置文件中更改插件目录：
[mysqld]
plugin_dir="D:/mysql57/lib/plugin/"
插件目录中有较多插件，这是windows中的个数。接下来将安装密码策略的插件validate_password.dll。
方法一：启动服务时添加
# mysqld --plugin-load="validate_password.dll" --validate-password=FORCE_PLUS_PERMANENT
--plugin-load :服务启动时重新加载插件
--plugin-load-add ：对当前插件的补充
-early-plugin-load ：加载在初始化插件及存储引擎之前的插件
--plugin-load=x --plugin-load-add=y 等价于 --plugin-load="x;y"
--plugin-load-add=y --plugin-load=x 等价于 --plugin-load=x
方法二：配置文件中添加(一般不用方法一)，随服务启动生效。
[mysqld]
plugin-load=validate_password.dll
validate-password = FORCE_PLUS_PERMANENT
# validate-password =ON/OFF/FORCE/FORCE_PLUS_PERMANENT: 是否使用该插件(及强制/永久强制使用)
方法三：在线添加(如不打算重启服务，可同时使用方法二和方法三)
#在线添加
mysql> INSTALL PLUGIN validate_password SONAME 'validate_password.dll';
#在线卸载
mysql> UNINSTALL PLUGIN validate_password;部分插件安装结果(第一行记录为刚才安装的)：
+----------------------------+---------------+--------------------+----------------------+-----------------------+
| plugin_name | plugin_status | plugin_type | load_option | plugin_library |
+----------------------------+---------------+--------------------+----------------------+-----------------------+
| validate_password | ACTIVE | VALIDATE PASSWORD | FORCE_PLUS_PERMANENT | validate_password.dll |
| sha256_password | ACTIVE | AUTHENTICATION | FORCE | NULL |
| PERFORMANCE_SCHEMA | ACTIVE | STORAGE ENGINE | FORCE | NULL |
| partition | ACTIVE | STORAGE ENGINE | ON | NULL |
| ngram | ACTIVE | FTPARSER | ON | NULL |
| mysql_native_password | ACTIVE | AUTHENTICATION | FORCE | NULL |
| MyISAM | ACTIVE | STORAGE ENGINE | FORCE | NULL |
查看插件 validate_password 相关变量：
mysql> show global variables like '%validate_password%';
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password_dictionary_file | |
| validate_password_length | 8 |
| validate_password_mixed_case_count | 1 |
| validate_password_number_count | 1 |
| validate_password_policy | MEDIUM |
| validate_password_special_char_count | 1 |
+--------------------------------------+--------+validate_password_dictionary_file ：验证密码的字典文件,与之相同的不可使用
validate_password_length ：密码最少长度
validate_password_number_count ：最少数字字符数
validate_password_mixed_case_count ：最少大写和小写字符数(同时有大写和小写)
validate_password_special_char_count ：最少特殊字符数
validate_password_policy ：密码安全策略：
0/LOW：只限长度,
1/MEDIUM：限制长度、数字、字母、特殊字符
2/STRONG：限制长度、数字、字母、特殊字符、字典
查看插件 validate_password 相关状态：
mysql> SHOW STATUS LIKE 'validate_password%';
+-----------------------------------------------+---------------------+
| Variable_name | Value |
+-----------------------------------------------+---------------------+
| validate_password_dictionary_file_last_parsed | 2018-03-05 12:13:06 |
| validate_password_dictionary_file_words_count | 0 |
+-----------------------------------------------+---------------------+validate_password_dictionary_file_last_parsed ：字典文件最近读取时间
validate_password_dictionary_file_words_count ：从字典文件的单词数
测试(当前默认策略：validate_password_policy=MEDIUM)
mysql> create user test@'localhost' identified by '12345678';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> create user test@'localhost' identified by 'Aa_12345';
Query OK, 0 rows affected (0.03 sec)
validate_password_dictionary_file 字典文件可以排除关键字，如不允许密码中使用文件中的字符串。
字典文件满足以下条件：
1. 密码策略为：STRONG
2. 文件中的字符串每行一个
3. 文件中符串每为小写,不区分大小写
4. 文件最大为 1MB
5. 文件字符集为utf8
6. 随时修改不用重启服务
7. 文件可读配置文件内容：D:/mysql57/lib/plugin/dictionary_file
12345
aa_12345在线更改变量：
mysql> set global validate_password_dictionary_file = "D:/mysql57/lib/plugin/dictionary_file";
mysql> set global validate_password_policy = STRONG;
在线更改变量有一个 bug，由于缓存不自动刷新原因，字典文件对于已经存在的插件缓存不会变，所以在线更改上面两个变量虽然可以更改，但不会刷新缓存(Bug #66697：need ability to flush password validation dictionary file) 。因此在配置文件中设置，并且重启服务重新加载插件。
plugin-load=validate_password.dll
validate-password = FORCE_PLUS_PERMANENT
validate_password_dictionary_file = "D:/mysql57/lib/plugin/dictionary_file"
validate_password_policy = STRONG测试结果：
mysql> show global variables like '%validate_password%';
+--------------------------------------+---------------------------------------+
| Variable_name | Value |
+--------------------------------------+---------------------------------------+
| validate_password_dictionary_file | D:/mysql57/lib/plugin/dictionary_file |
| validate_password_length | 8 |
| validate_password_mixed_case_count | 1 |
| validate_password_number_count | 1 |
| validate_password_policy | STRONG |
| validate_password_special_char_count | 1 |
+--------------------------------------+---------------------------------------+
6 rows in set, 1 warning (0.00 sec)
mysql> create user test@'localhost' identified by 'Aa_12346';
Query OK, 0 rows affected (0.07 sec)
mysql> create user test1@'localhost' identified by 'Aa_12345';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql>使用密码 “Aa_12346” 不会报错，而使用密码 “Aa_12345”则出现错误，因为该密码与字典文件中的 “aa_12345”一样。
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