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设置更改root密码、连接mysql、mysql常用命令

设置更改root密码、连接mysql、mysql常用命令

作者: XiaoMing丶 | 来源:发表于2018-12-05 23:36 被阅读0次

    目录

    一、设置更改root密码
    二、连接mysql
    三、mysql常用命令

    一、设置更改root密码

    • 检查mysql服务是否启动
    [root@minglinux-01 ~] ps aux |grep mysql
    root        828  0.0  0.0 115640  1824 ?        S    03:15   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/minglinux-01.pid
    mysql      1199  0.0 24.7 1320112 462216 ?      Sl   03:15   0:59 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=minglinux-01.err --pid-file=/data/mysql/minglinux-01.pid --socket=/tmp/mysql.sock --port=3306
    root       6529  0.0  0.0 112724   984 pts/0    S+   21:34   0:00 grep --color=auto mysql
    
    • mysql启动
    [root@minglinux-01 ~] mysql
    -bash: mysql: 未找到命令   //只单独输入一个mysql命令是不行的,因为Mysql相关命令在/usr/local/mysql/bin路径下,但该路径不在环境变量PATH中
    [root@minglinux-01 ~] echo $PATH
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
    [root@minglinux-01 ~] export PATH=$PATH:/usr/local/mysql/bin/   //临时生效,系统重启后失效
    [root@minglinux-01 ~] echo $PATH
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/usr/local/mysql/bin/
    [root@minglinux-01 ~] echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile       //永久生效
    [root@minglinux-01 ~] source /etc/profile  
    [root@minglinux-01 ~] mysql -uroot -p  //指定使用root用户登录mysql,-p参数用于指定密码。root用户是MySQL自带的管理员账户,默认是没有密码的。
    Enter password: 
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 2
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql>   
    mysql> quit  //quit退出mysql
    Bye
    
    • 给root用户设定密码
    [root@minglinux-01 ~] mysqladmin -uroot password '123456'
    Warning: Using a password on the command line interface can be insecure.  //警告明文密码不安全
    [root@minglinux-01 ~] mysql -uroot  //不指定密码无法登录,
    ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
    [root@minglinux-01 ~] mysql -uroot -p'123456'
    Warning: Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 8
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql> 
    
    

    输入密码时需要加-p选项,后面可以直接跟密码。-p选项后面不可以有空格,密码可以不加单引号(但是密码中有特殊字符时就会出问题,所以最好还是加上单引号)。当然,-p选项后面也可以不加密码,以和用户交互的方式输入密码。

    • 再次修改root用户密码
    [root@minglinux-01 ~] mysqladmin -uroot -p'123456' password 'toor'
    Warning: Using a password on the command line interface can be insecure.
    [root@minglinux-01 ~] mysql -uroot -p'toor'
    Warning: Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 13
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql> 
    
    
    • 在不知道root密码的情况下修改root密码
      修改/etc/my.cnf配置文件,增加一行skip-grant
    [root@minglinux-01 ~] vim /etc/my.cnf
    
      7 [mysqld]
      8 skip-grant   //忽略授权,即用户登录mysql时不需要密码
    
    [root@minglinux-01 ~] /etc/init.d/mysqld restart
    Shutting down MySQL.. SUCCESS! 
    Starting MySQL. SUCCESS! 
    ···
    [root@minglinux-01 ~] mysql -uroot //无需密码直接登录
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 1
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql> 
    
    • 通过修改mysql库中的user表来修改root密码
    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    4 rows in set (0.00 sec)
    
    mysql> use mysql;
    Reading table information for completion of table and column names
    You can turn off this feature to get a quicker startup with -A
    
    Database changed
    mysql> select * from user; //user表这记录了用户名、密码、权限等信息
    mysql> select password from user;  //密码信息是加密的字符串,这些加密的字符串由password函数生成,所以修改密码时也需要password函数对密码进行加密
    +-------------------------------------------+
    | password                                  |
    +-------------------------------------------+
    | *9CFBBC772F3F6C106020035386DA5BBBF1249A11 |
    |                                           |
    |                                           |
    |                                           |
    |                                           |
    |                                           |
    +-------------------------------------------+
    6 rows in set (0.00 sec)
    
    mysql> update user set password=password('123456') where user='root'; //修改密码为123456
    Query OK, 4 rows affected (0.00 sec)
    Rows matched: 4  Changed: 4  Warnings: 0
    
    
    • 测试
      删除/etc/my.cnf中的skip-grant后重启mysql再进行测试
    [root@minglinux-01 ~] vim /etc/my.cnf
    [root@minglinux-01 ~] /etc/init.d/mysqld restart
    Shutting down MySQL.. SUCCESS! 
    Starting MySQL. SUCCESS! 
    [root@minglinux-01 ~] mysql -uroot -p'123456'
    Warning: Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 1
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql> 
    

    二、连接mysql

    mysql -uroot -p123456 //连接本机
    mysql -uroot -p123456 -h127.0.0.1 -P3306 //指定IP和端口号远程连接
    mysql -uroot -p123456 -S/tmp/mysql.sock //Socket连接
    mysql -uroot -p123456 -e ''show databases'' //连接后执行操作,常用于shell脚本

    [root@minglinux-01 ~] mysql -uroot -p123456 -e 'show databases' 
    Warning: Using a password on the command line interface can be insecure.
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    

    三、mysql常用命令

    • 查询库 show databases
    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    4 rows in set (0.00 sec)
    
    • 切换库 use mysql
    mysql> use mysql;
    Reading table information for completion of table and column names
    You can turn off this feature to get a quicker startup with -A
    
    Database changed
    
    • 查看库里的表 show tables
    mysql> show tables;
    +---------------------------+
    | Tables_in_mysql           |
    +---------------------------+
    | columns_priv              |
    | db                        |
    | event                     |
    | func                      |
    | general_log               |
    | help_category             |
    | help_keyword              |
    | help_relation             |
    | help_topic                |
    | innodb_index_stats        |
    | innodb_table_stats        |
    | ndb_binlog_index          |
    | plugin                    |
    | proc                      |
    | procs_priv                |
    | proxies_priv              |
    | servers                   |
    | slave_master_info         |
    | slave_relay_log_info      |
    | slave_worker_info         |
    | slow_log                  |
    | tables_priv               |
    | time_zone                 |
    | time_zone_leap_second     |
    | time_zone_name            |
    | time_zone_transition      |
    | time_zone_transition_type |
    | user                      |
    +---------------------------+
    28 rows in set (0.00 sec)
    
    • 查看表里的字段 desc tb_name
    mysql> desc user;
    +------------------------+-----------------------------------+------+-----+-----------------------+-------+
    | Field                  | Type                              | Null | Key | Default               | Extra |
    +------------------------+-----------------------------------+------+-----+-----------------------+-------+
    | Host                   | char(60)                          | NO   | PRI |                       |       |
    | User                   | char(16)                          | NO   | PRI |                       |       |
    | Password               | char(41)                          | NO   |     |                       |       |
    | Select_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Insert_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Update_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Delete_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Drop_priv              | enum('N','Y')                     | NO   |     | N                     |       |
    | Reload_priv            | enum('N','Y')                     | NO   |     | N                     |       |
    | Shutdown_priv          | enum('N','Y')                     | NO   |     | N                     |       |
    | Process_priv           | enum('N','Y')                     | NO   |     | N                     |       |
    | File_priv              | enum('N','Y')                     | NO   |     | N                     |       |
    | Grant_priv             | enum('N','Y')                     | NO   |     | N                     |       |
    | References_priv        | enum('N','Y')                     | NO   |     | N                     |       |
    | Index_priv             | enum('N','Y')                     | NO   |     | N                     |       |
    | Alter_priv             | enum('N','Y')                     | NO   |     | N                     |       |
    | Show_db_priv           | enum('N','Y')                     | NO   |     | N                     |       |
    | Super_priv             | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_tmp_table_priv  | enum('N','Y')                     | NO   |     | N                     |       |
    | Lock_tables_priv       | enum('N','Y')                     | NO   |     | N                     |       |
    | Execute_priv           | enum('N','Y')                     | NO   |     | N                     |       |
    | Repl_slave_priv        | enum('N','Y')                     | NO   |     | N                     |       |
    | Repl_client_priv       | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_view_priv       | enum('N','Y')                     | NO   |     | N                     |       |
    | Show_view_priv         | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_routine_priv    | enum('N','Y')                     | NO   |     | N                     |       |
    | Alter_routine_priv     | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_user_priv       | enum('N','Y')                     | NO   |     | N                     |       |
    | Event_priv             | enum('N','Y')                     | NO   |     | N                     |       |
    | Trigger_priv           | enum('N','Y')                     | NO   |     | N                     |       |
    | Create_tablespace_priv | enum('N','Y')                     | NO   |     | N                     |       |
    | ssl_type               | enum('','ANY','X509','SPECIFIED') | NO   |     |                       |       |
    | ssl_cipher             | blob                              | NO   |     | NULL                  |       |
    | x509_issuer            | blob                              | NO   |     | NULL                  |       |
    | x509_subject           | blob                              | NO   |     | NULL                  |       |
    | max_questions          | int(11) unsigned                  | NO   |     | 0                     |       |
    | max_updates            | int(11) unsigned                  | NO   |     | 0                     |       |
    | max_connections        | int(11) unsigned                  | NO   |     | 0                     |       |
    | max_user_connections   | int(11) unsigned                  | NO   |     | 0                     |       |
    | plugin                 | char(64)                          | YES  |     | mysql_native_password |       |
    | authentication_string  | text                              | YES  |     | NULL                  |       |
    | password_expired       | enum('N','Y')                     | NO   |     | N                     |       |
    +------------------------+-----------------------------------+------+-----+-----------------------+-------+
    43 rows in set (0.00 sec)
    
    
    • 查看建表语句 show create table tb_name\G
    mysql> show create table user\G;
    *************************** 1. row ***************************
           Table: user
    Create Table: CREATE TABLE `user` (
      `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',
      `User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',
      `Password` char(41) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '',
      `Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Reload_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Shutdown_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Process_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `File_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Show_db_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Super_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Repl_slave_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Repl_client_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_user_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Event_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `Create_tablespace_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      `ssl_type` enum('','ANY','X509','SPECIFIED') CHARACTER SET utf8 NOT NULL DEFAULT '',
      `ssl_cipher` blob NOT NULL,
      `x509_issuer` blob NOT NULL,
      `x509_subject` blob NOT NULL,
      `max_questions` int(11) unsigned NOT NULL DEFAULT '0',
      `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
      `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
      `max_user_connections` int(11) unsigned NOT NULL DEFAULT '0',
      `plugin` char(64) COLLATE utf8_bin DEFAULT 'mysql_native_password',
      `authentication_string` text COLLATE utf8_bin,
      `password_expired` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
      PRIMARY KEY (`Host`,`User`)
    ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges'
    1 row in set (0.00 sec)
    
    ERROR: 
    No query specified
    
    

    命令加\G的目的是让列出来的结果竖排显示,这样看起来更清晰。

    • 查看当前用户 select user()
    mysql> select user();
    +----------------+
    | user()         |
    +----------------+
    | root@localhost |  
    +----------------+
    1 row in set (0.00 sec)
    
    [root@minglinux-01 ~] mysql -uroot -p123456 -h192.168.162.130 //
    Warning: Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 9
    Server version: 5.6.39-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
    
    mysql> select user();
    +-------------------+
    | user()            |
    +-------------------+
    | root@minglinux-01 |   //这里ip地址192.168.162.130被反解析到主机名minglinux-01
    +-------------------+
    1 row in set (0.00 sec)
    
    
    • 查看当前使用的数据库 select databsase()
    mysql> select database();
    +------------+
    | database() |
    +------------+
    | NULL       |    //当前为NULL
    +------------+
    1 row in set (0.00 sec)
    
    mysql> use mysql
    Reading table information for completion of table and column names
    You can turn off this feature to get a quicker startup with -A
    
    Database changed
    mysql> use mysql;
    Database changed
    mysql> select database();
    +------------+
    | database() |
    +------------+
    | mysql      |
    +------------+
    1 row in set (0.00 sec)
    
    
    • 创建库 create database db1
    mysql> create database db1;
    Query OK, 1 row affected (0.00 sec)
    
    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | db1                |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    5 rows in set (0.00 sec)
    
    
    • 创建表 use db1; create table t1(id int(4), name char(40))
    mysql> use db1;
    Database changed
    mysql> create table t1(`id` int(4), `name` char(40));
    Query OK, 0 rows affected (0.01 sec)
    
    mysql> show tables;
    +---------------+
    | Tables_in_db1 |
    +---------------+
    | t1            |
    +---------------+
    1 row in set (0.00 sec)
    mysql> show create table t1\G;
    *************************** 1. row ***************************
           Table: t1
    Create Table: CREATE TABLE `t1` (
      `id` int(4) DEFAULT NULL,
      `name` char(40) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1
    1 row in set (0.00 sec)
    
    ERROR: 
    No query specified
    mysql> drop table t1;
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> create table t1(`id` int(4),`name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    Query OK, 0 rows affected (0.01 sec)
    
    mysql> show create table t1\G;
    *************************** 1. row ***************************
           Table: t1
    Create Table: CREATE TABLE `t1` (
      `id` int(4) DEFAULT NULL,
      `name` char(40) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8  //字符集已改成utf8
    1 row in set (0.00 sec)
    
    ERROR: 
    No query specified
    
    
    • 查看当前数据库版本 select version()
    mysql> select version();
    +------------+
    | version()  |
    +------------+
    | 5.6.39-log |
    +------------+
    1 row in set (0.00 sec)
    
    • 查看数据库状态 show status
    mysql> show status;
    +-----------------------------------------------+-------------+
    | Variable_name                                 | Value       |
    +-----------------------------------------------+-------------+
    | Aborted_clients                               | 0           |
    | Aborted_connects                              | 2           |
    | Binlog_cache_disk_use                         | 0           |
    | Binlog_cache_use                              | 0           |
    | Binlog_stmt_cache_disk_use                    | 0           |
    | Binlog_stmt_cache_use                         | 4           |
    | Bytes_received                                | 1246        |
    | Bytes_sent                                    | 22400       |
    | Com_admin_commands                            | 0           |
    | Com_assign_to_keycache                        | 0           |
    | Com_alter_db                                  | 0           |
    | Com_alter_db_upgrade                          | 0           |
    | Com_alter_event                               | 0           |
    | Com_alter_function                            | 0           |
    | Com_alter_procedure                           | 0           |
    | Com_alter_server                              | 0           |
    | Com_alter_table                               | 0           |
    | Com_alter_tablespace                          | 0           |
    | Com_alter_user                                | 0           |
    | Com_analyze                                   | 0           |
    | Com_begin                                     | 0           |
    | Com_binlog                                    | 0           |
    | Com_call_procedure                            | 0           |
    | Com_change_db                                 | 3           |
    ···
    ···
    +-----------------------------------------------+-------------+
    341 rows in set (0.00 sec)
    
    
    • 查看各参数 show variables; show variables like 'max_connect%'
    mysql> show variables;  //这些参数均可以在my.cnf中定义
    mysql> show variables like 'max_connect%';   //指定查看某个或某些参数
    +--------------------+-------+
    | Variable_name      | Value |
    +--------------------+-------+
    | max_connect_errors | 100   |
    | max_connections    | 151   |
    +--------------------+-------+
    2 rows in set (0.00 sec)
    mysql> show variables like 'slow%';
    +---------------------+-----------------------------------+
    | Variable_name       | Value                             |
    +---------------------+-----------------------------------+
    | slow_launch_time    | 2                                 |
    | slow_query_log      | OFF                               |
    | slow_query_log_file | /data/mysql/minglinux-01-slow.log |
    +---------------------+-----------------------------------+
    3 rows in set (0.00 sec)
    
    
    • 修改参数 set global max_connect_errors=1000
    mysql> set global max_connect_errors=1000; 
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> show variables like 'max_connect%';
    +--------------------+-------+
    | Variable_name      | Value |
    +--------------------+-------+
    | max_connect_errors | 1000  |
    | max_connections    | 151   |
    +--------------------+-------+
    2 rows in set (0.00 sec)
    
    

    修改参数的值在内存中生效,重启失效。在/etc/my.cnf文件中修改则永久有效

    • 查看队列 show processlist; show full processlist
    mysql> show processlist;
    +----+------+-----------+------+---------+------+-------+------------------+
    | Id | User | Host      | db   | Command | Time | State | Info             |
    +----+------+-----------+------+---------+------+-------+------------------+
    | 11 | root | localhost | NULL | Query   |    0 | init  | show processlist |
    +----+------+-----------+------+---------+------+-------+------------------+
    1 row in set (0.00 sec)
    mysql> show full processlist;
    +----+------+-----------+------+---------+------+-------+-----------------------+
    | Id | User | Host      | db   | Command | Time | State | Info                  |
    +----+------+-----------+------+---------+------+-------+-----------------------+
    | 11 | root | localhost | NULL | Query   |    0 | init  | show full processlist |
    +----+------+-----------+------+---------+------+-------+-----------------------+
    1 row in set (0.00 sec)
    

    使用show processlist显示的最后一列(info)可能不完整,使用show full processlist会显示完整

    • Mysql历史命令记录文件
    [root@minglinux-01 ~] ls -a|grep mysql_history
    .mysql_history
    [root@minglinux-01 ~] cat .mysql_history 
    _HiStOrY_V2_
    show\040database;
    show\040databases;
    use\040mysql;
    select\040*\040from\040user;
    show\040databases;
    use\040mysql;
    show\040tables;
    desc\040user;
    show\040create\040table\040user\134G;
    select\040user();
    select\040database();
    use\040mysql
    use\040mysql;
    select\040database();
    create\040database\040db1;
    show\040databases;
    use\040db1;
    create\040table\040t1(`id`\040int(4),\040`name`\040char(40));
    show\040tables;
    show\040create\040table\040t1\134G;
    drop\040table\040t1;
    create\040table\040t1(`id`\040int(4),`name`\040char(40))\040ENGINE=InnoDB\040DEFAULT\040CHARSET=utf8;
    show\040create\040table\040t1\134G;
    select\040version();
    show\040status;
    show\040variables;
    show\040variables\040like\040'max_connect%'
    show\040variables\040like\040'max_connect%';
    show\040variables\040like\040'slow%';
    set\040global\040max_connect_errors=1000;\040
    show\040variables\040like\040'max_connect%';
    show\040processlist;
    show\040full\040processlist;
    
    
    扩展

    mysql5.7 root密码更改 http://www.apelearn.com/bbs/thread-7289-1-1.html
    myisam 和innodb引擎对比 http://www.pureweber.com/article/myisam-vs-innodb/
    知乎上的答案 https://www.zhihu.com/question/20596402
    mysql 配置详解:https://www.jb51.net/article/48082.htm
    mysql调优: http://www.aminglinux.com/bbs/thread-5758-1-1.html
    同学分享的亲身mysql调优经历: http://www.apelearn.com/bbs/thread-11281-1-1.html

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