- 13.1 設置更改root密碼
- 13.2 連接mysql
- 13.3 mysql常用命令
- 擴展
- mysql5.7 root密碼更改 http://www.apelearn.com/bbs/thread-7289-1-1.html
- myisam 和innodb引擎對比 http://www.pureweber.com/article/myisam-vs-innodb/
- mysql 配置詳解： http://blog.linuxeye.com/379.html
- mysql調優： http://www.aminglinux.com/bbs/thread-5758-1-1.html
- 同學分享的親身mysql調優經歷： http://www.apelearn.com/bbs/thread-11281-1-1.html
# 13.1 設置更改root密碼
- root用戶是mysql的超級管理員用戶，和linux系統的root類似，不過和Linux的不一樣
默認root 密碼是空的
- 先看下自己虛擬機mysql服務有沒有啓動,如果沒有就使用/etc/init.d/mysqld start 命令啓動mysql服務
```
[root@localhost ~]# ps aux |grep mysql
root 926 0.0 0.1 115392 1692 ? S 23:10 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/localhost.pid
mysql 1300 0.4 45.2 1300792 452716 ? Sl 23:10 0:00 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/localhost.err --pid-file=/data/mysql/localhost.pid --socket=/tmp/mysql.sock
root 2338 0.0 0.0 112684 980 pts/0 S+ 23:12 0:00 grep --color=auto mysql
[root@localhost ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
[root@localhost ~]# !ps
ps aux |grep mysql
root 2374 0.0 0.1 113264 1588 pts/0 S 23:13 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/localhost.pid
mysql 2512 5.1 44.9 1300792 449964 pts/0 Sl 23:13 0:00 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/localhost.err --pid-file=/data/mysql/localhost.pid --socket=/tmp/mysql.sock
root 2536 0.0 0.0 112680 980 pts/0 S+ 23:13 0:00 grep --color=auto mysql
[root@localhost ~]# mysql -uroot
-bash: mysql: 未找到命令
[root@localhost ~]#
```
- 未找到命令，mysql命令不存在，因爲咱們安裝的mysql在/usr/local/mysql/bin/mysql 目錄下，而這個並沒有在環境變量PATH裏面，所以它會報錯，說這個命令沒有找到
- 爲了方便使用mysql服務，需要把這個PATH做一個更改，或者將mysql目錄加入到環境變量裏
```
[root@localhost ~]# ls /usr/local/mysql/bin/mysql
/usr/local/mysql/bin/mysql
[root@localhost ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost ~]# export PATH=$PATH:/usr/local/mysql/bin/
[root@localhost ~]# mysql -uroot
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 如果想要永久生效，需要把export PATH=$PATH:/usr/local/mysql/bin/ 放到/etc/profile 下面,放到最後一排
```
[root@localhost ~]# vi /etc/profile
# /etc/profile
done
unset i
unset -f pathmunge
export PATH=$PATH:/usr/local/mysql/bin/
~
:wq
```
- 如果沒有上面的命令export PATH=$PATH:/usr/local/mysql/bin/ 執行，只更改了環境變量還需要執行 source /etc/profile
```
[root@localhost ~]# vi /etc/profile
[root@localhost ~]# source /etc/profile
```
- 設置root密碼 mysql -uroot -p ,你如果不想設置密碼，直接按回車就好了，密碼爲空
```
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 這樣就進來了，進來之後可以操作關於mysql的一些行爲，先退出來，使用quit
- 怎麼樣去設置root的密碼呢？
```
[root@localhost ~]# mysqladmin -uroot password 'aminglinux.1'
Warning: Using a password on the command line interface can be insecure.
[root@localhost ~]#
```
- 現在再登錄mysql 就會說你這樣把密碼顯示在外面了，這樣不×××全,
- 因爲他現在已經設置密碼了，需要密碼，需要-p 然後輸入它的密碼 就可以正常進入到命令行了
```
[root@localhost ~]# mysql -uroot
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@localhost ~]#
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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>
```
- 你已經知道密碼了，現在需要更改它
```
mysql> quit
Bye
[root@localhost ~]# mysqladmin -uroot -p'aminglinux.1' password 'aminglinux.2'
Warning: Using a password on the command line interface can be insecure.
[root@localhost ~]#
```
- 再使用新的密碼登錄 mysql -uroot -p'aminglinux.2' 這個地方可加單引號 也可以不加，最好加下，怕有特殊符號，不識別
```
[root@localhost ~]# mysql -uroot -p'aminglinux.2'
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: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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>
```
- 這是知道mysql ，root密碼，假如有另一種情況，你不知道mysql密碼 怎麼改呢？
- 步驟如下:
- 密碼重置
- vi /etc/my.cnf//增加skip-grant
- 重啓mysql服務 /etc/init.d/mysqld restart
- mysql -uroot
- use mysql;
- update user set password=password('aminglinux') where user='root';
- 先打開配置文件/etc/my.cnf 在mysqld 下面 加入一行 skip-grant （忽略授權）也就是說在操作mysql這裏的時候 不用用戶名密碼了 ，直接登錄
```
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
skip-grant
datadir=/data/mysql
socket=/tmp/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d
~
~
:wq
```
- 改了配置文件之後，還要重啓一下mysqld 服務才能生效
```
[root@localhost ~]# vim /etc/my.cnf
[root@localhost ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@localhost ~]#
```
- 這個時候再進入mysql, 根本就不要密碼了
- 進來之後，還需要更改一個表，這裏面有一個庫，叫mysql庫
- use mysql; 切換到庫裏面，
- 切換到mysql庫裏面 需要去更改一個表，
```
[root@localhost ~]# mysql -uroot
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> 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>
```
- 哪一個表是存用戶密碼的呢，user表，咱麼不妨先看下錶
- 這裏面就是存一些用戶名 密碼
```
Database changed
mysql> select * from user;
| | | 0 | 0 | 0 | 0 | mysql_native_password | | N |
| 127.0.0.1 | root | | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | mysql_native_password | | N |
| ::1 | root | | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | mysql_native_password | | N |
| localhost | | | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | mysql_native_password | NULL | N |
| localhost.localdomain | | | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | N | | | | | 0 | 0 | 0 | 0 | mysql_native_password | NULL | N |
+-----------------------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+-----------------------+-----------------------+------------------+
6 rows in set (0.00 sec)
mysql>
現在我們要改這個表，使用這個命令
mysql> select password from user where user='root';
+-------------------------------------------+
| password |
+-------------------------------------------+
| *C2586DB1E5698A5F1DC57808497DA087CC1EF767 |
| |
| |
| |
+-------------------------------------------+
4 rows in set (0.00 sec)
mysql>
```
- 這個字符串就是用password這個函數來生成的，所以我們要改這個密碼的時候，也需要用這個函數個給它做一個加密
```
mysql> update user set password=password('aminglinux') where user='root';
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
mysql> quit
Bye
[root@localhost ~]#
```
- 退出來之後還要做一個操作，把my.cnf 裏面的skip-grant 去掉,如果不把這個去掉，所有的用戶進來都不需要密碼，這樣非常的不安全
```
[root@localhost ~]# vi /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d
~
~
:wq
```
- 重啓mysqld 服務,再重新試下，使用新的密碼 aminglinux 試下進入
```
[root@localhost ~]# vi /etc/my.cnf
[root@localhost ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
[root@localhost ~]# mysql -uroot -paminglinux
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 2
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 回顧步驟
```
[root@localhost ~]# vi /etc/my.cnf --> skip-grant ,restart, 2 mysql -uroot; use mysql; 3 update ... 3 vi /etc/my.cnf --> delete skip-grant 4. restart ^C
[root@localhost ~]#
```
# 13.2 連接MySQL
- 常用連接接mysql的命令
- 本地連接mysql
- 指定用戶密碼訪問
- mysql -uroot -p123456
```
[root@localhost ~]# mysql -uroot -paminglinux
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 4
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 使用ip端口連接遠程機器
- mysql -uroot -p123456 -h[遠程mysql主機IP] -P[端口]
```
[root@localhost ~]# mysql -uroot -paminglinux -h127.0.0.1 -P3306
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 5
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 使用sock方式連接（這種情況只適合在本機使用）如爲指定IP就用sock訪問，默認用/tmp/mysql.sock
```
[root@localhost ~]# mysql -uroot -paminglinux -S/tmp/mysql.sock
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 6
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> quit
Bye
[root@localhost ~]#
```
- 連接mysql之後操作一些命令,(這種情況使用腳本里面)
```
[root@localhost ~]# mysql -uroot -paminglinux -e "show databases" 列出所有庫
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
[root@localhost ~]#
```
# 13.3 mysql 常用的命令
- 查詢庫 show databases;
- 切換庫 use mysql;
- 查看庫裏的表 show tables;
- 查看錶裏的字段 desc tb_name;
- 查看建表語句 show create table tb_name\G;
- 查看當前用戶 select user();
- 查看當前使用的數據庫 select databsase();
- 在mysql裏面執行的命令，在外面不能去執行，反而在外面執行的命令在mysql裏面來，也不行，
- 查看都有什麼數據庫 show databases;
```
[root@localhost ~]# mysql -uroot -paminglinux
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: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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>
```
- 切換到哪一個庫下面
```
[root@localhost ~]# mysql -uroot -paminglinux
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: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.04 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>
```
- 查看庫裏的表 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)
mysql>
```
- [x] 注意mysql裏面的操作命令後面要加一個分號 ; 這個在外面linux是不一樣的，需要用；作爲命令的結尾，不然會出問題
- 庫是表組成的，表是由字段組成的， 查看錶裏的字段 desc tb_name;
- 我們來查看user這個表裏有哪些字段
```
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)
mysql>
```
- Field 下面是名字， 字段 是字符格式還是字母格式
- 現在想看看 這個表示怎麼創建的show create tab\G; \G 是表示豎排顯示，如果不加 會很亂，有很多橫槓
-
```
mysql> mysql> show create tab\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 (0.01 sec)
ERROR:
No query specified
mysql>
```
- 查看當前用戶 select user();
```
mysql> select user();
+----------------+
| user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
mysql>
```
- 咱們再換一個方法登錄
```
[root@localhost ~]# mysql -uroot -paminglinux -h127.0.0.1
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 2
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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@localhost |
+----------------+
1 row in set (0.00 sec)
mysql>
```
- 換了還是localhost ，因爲127.0.0.1 就是root 自己，就是本地
- 那再換一個方式登錄
```
[root@localhost ~]# mysql -uroot -paminglinux -h192.168.202.131
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 6
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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@localhost |
+----------------+
1 row in set (0.00 sec)
mysql>
```
- 按向上的方向鍵也會有上一個命令歷史，也有記錄命令歷史的功能，那它的記錄命令歷史的文件在哪裏
```
[root@localhost ~]# ls -la
總用量 76
dr-xr-x---. 3 root root 197 10月 28 13:28 .
dr-xr-xr-x. 18 root root 236 10月 5 15:52 ..
-rw-------. 1 root root 1261 10月 5 22:26 anaconda-ks.cfg
-rw-------. 1 root root 29165 10月 27 00:09 .bash_history
-rw-r--r--. 1 root root 18 12月 29 2013 .bash_logout
-rw-r--r--. 1 root root 176 12月 29 2013 .bash_profile
-rw-r--r--. 1 root root 176 12月 29 2013 .bashrc
-rw-r--r--. 1 root root 100 12月 29 2013 .cshrc
-rw-------. 1 root root 308 10月 28 13:28 .mysql_history
drwxr-----. 3 root root 19 10月 5 21:56 .pki
-rw-------. 1 root root 1024 10月 23 22:25 .rnd
-rw-r--r--. 1 root root 129 12月 29 2013 .tcshrc
-rw-------. 1 root root 8666 10月 25 23:50 .viminfo
[root@localhost ~]#
```
- 其實有一個mysql_history，可以用less看下
- 它同樣也支持ctrl l 請屏，直接到最上面
```
[root@localhost ~]# less .mysql_history
_HiStOrY_V2_
user\040mysql;
use\040mysql;
select\040*\040from\040user;
select\040passwrod\040from\040user\040where\040user=root;
select\040passwrod\040from\040user\040where\040user='root';
show\040databases;
use\040mysql;
show\040tables;
desc\040user;
show\040create\040table\040user\134G;
select\040user();
.mysql_history (END)
[root@localhost ~]# less .mysql_history
[root@localhost ~]# !mysql
mysql -uroot -paminglinux
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: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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>
```
- 查看當前使用的數據庫 select databsase();當前的是空，再user mysql； 切換到mysql下，這是當前所在的庫 是哪一個庫
```
mysql> select database();
+------------+
| database() |
+------------+
| NULL |
+------------+
1 row in set (0.00 sec)
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
mysql> use mysql;
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| mysql |
+------------+
1 row in set (0.00 sec)
mysql>
```
- 創建庫 create database db1;
- 創建表 use db1; create table t1(`id` int(4), `name` char(40));
- 查看當前數據庫版本 select version();
- 查看數據庫狀態 show status;
- 查看各參數 show variables; show variables like 'max_connect%';
- 修改參數 set global max_connect_errors=1000;
- 查看隊列 show processlist; show full processlist;
1. 創建庫 create database db1; 多了一個db1庫
```
mysql> create database db1;
Query OK, 1 row affected (0.01 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db1 |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql>
```
- 切換到db1 下面去
```
mysql> use db1;
Database changed
mysql>
```
- 創建表 use db1; create table t1(`id` int(4), `name` char(40));
- show create table t1\G;也可以看到創建表的語句是什麼
```
mysql> create table t1(`id` int(4), `name` char(40));
Query OK, 0 rows affected (0.18 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>
```
- 先把這個表t1 先刪掉，再創建一個，定義CHARSET=utf8，
```
mysql> drop table t1;
Query OK, 0 rows affected (0.10 sec)
mysql> create table t1(`id` int(4), `name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.02 sec)
mysql>
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
1 row in set (0.00 sec)
ERROR:
No query specified
mysql>
```
- 再來看下 CHARSET 是不是變成了utf8，這是創建一個表
- 還可以查看當前數據庫的版本select version();
```
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.36 |
+-----------+
1 row in set (0.00 sec)
mysql>
```
- 查看數據庫狀態 show status;
```
mysql> show status;
+-----------------------------------------------+-------------+
| Variable_name | Value |
+-----------------------------------------------+-------------+
| Aborted_clients | 0 |
| Aborted_connects | 1 |
| Binlog_cache_disk_use | 0 |
| Binlog_cache_use | 0 |
| Binlog_stmt_cache_disk_use | 0 |
| Binlog_stmt_cache_use | 0 |
| Bytes_received | 1571 |
| Bytes_sent | 22751 |
| 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 |
| Com_change_master | 0 |
| Com_check | 0 |
| Com_checksum | 0 |
| Com_commit | 0 |
| Com_create_db | 1 |
| Com_create_event | 0 |
| Com_create_function | 0 |
| Com_create_index | 0 |
| Com_create_procedure | 0 |
| Com_create_server | 0 |
| Com_create_table | 2 |
| Com_create_trigger | 0 |
| Com_create_udf | 0 |
| Com_create_user | 0 |
| Com_create_view | 0 |
| Com_dealloc_sql | 0 |
| Com_delete | 0 |
| Com_delete_multi | 0 |
| Com_do | 0 |
| Com_drop_db | 0 |
| Com_drop_event | 0 |
| Com_drop_function | 0 |
| Com_drop_index | 0 |
| Com_drop_procedure | 0 |
| Com_drop_server | 0 |
| Com_drop_table | 1 |
| Com_drop_trigger | 0 |
| Com_drop_user | 0 |
| Com_drop_view | 0 |
| Com_empty_query | 0 |
| Com_execute_sql | 0 |
| Com_flush | 0 |
| Com_get_diagnostics | 0 |
| Com_grant | 0 |
| Com_ha_close | 0 |
| Com_ha_open | 0 |
| Com_ha_read | 0 |
| Com_help | 0 |
| Com_insert | 0 |
| Com_insert_select | 0 |
| Com_install_plugin | 0 |
| Com_kill | 0 |
| Com_load | 0 |
| Com_lock_tables | 0 |
| Com_optimize | 0 |
| Com_preload_keys | 0 |
| Com_prepare_sql | 0 |
| Com_purge | 0 |
| Com_purge_before_date | 0 |
| Com_release_savepoint | 0 |
| Com_rename_table | 0 |
| Com_rename_user | 0 |
| Com_repair | 0 |
| Com_replace | 0 |
| Com_replace_select | 0 |
| Com_reset | 0 |
| Com_resignal | 0 |
| Com_revoke | 0 |
| Com_revoke_all | 0 |
| Com_rollback | 0 |
| Com_rollback_to_savepoint | 0 |
| Com_savepoint | 0 |
| Com_select | 7 |
| Com_set_option | 0 |
| Com_signal | 0 |
| Com_show_binlog_events | 0 |
| Com_show_binlogs | 0 |
| Com_show_charsets | 0 |
| Com_show_collations | 0 |
| Com_show_create_db | 0 |
| Com_show_create_event | 0 |
| Com_show_create_func | 0 |
| Com_show_create_proc | 0 |
| Com_show_create_table | 2 |
| Com_show_create_trigger | 0 |
| Com_show_databases | 3 |
| Com_show_engine_logs | 0 |
| Com_show_engine_mutex | 0 |
| Com_show_engine_status | 0 |
| Com_show_events | 0 |
| Com_show_errors | 0 |
| Com_show_fields | 28 |
| Com_show_function_code | 0 |
| Com_show_function_status | 0 |
| Com_show_grants | 0 |
| Com_show_keys | 0 |
| Com_show_master_status | 0 |
| Com_show_open_tables | 0 |
| Com_show_plugins | 0 |
| Com_show_privileges | 0 |
| Com_show_procedure_code | 0 |
| Com_show_procedure_status | 0 |
| Com_show_processlist | 0 |
| Com_show_profile | 0 |
| Com_show_profiles | 0 |
| Com_show_relaylog_events | 0 |
| Com_show_slave_hosts | 0 |
| Com_show_slave_status | 0 |
| Com_show_status | 1 |
| Com_show_storage_engines | 0 |
| Com_show_table_status | 0 |
| Com_show_tables | 2 |
| Com_show_triggers | 0 |
| Com_show_variables | 0 |
| Com_show_warnings | 0 |
| Com_slave_start | 0 |
| Com_slave_stop | 0 |
| Com_stmt_close | 0 |
| Com_stmt_execute | 0 |
| Com_stmt_fetch | 0 |
| Com_stmt_prepare | 0 |
| Com_stmt_reprepare | 0 |
| Com_stmt_reset | 0 |
| Com_stmt_send_long_data | 0 |
| Com_truncate | 0 |
| Com_uninstall_plugin | 0 |
| Com_unlock_tables | 0 |
| Com_update | 0 |
| Com_update_multi | 0 |
| Com_xa_commit | 0 |
| Com_xa_end | 0 |
| Com_xa_prepare | 0 |
| Com_xa_recover | 0 |
| Com_xa_rollback | 0 |
| Com_xa_start | 0 |
| Compression | OFF |
| Connection_errors_accept | 0 |
| Connection_errors_internal | 0 |
| Connection_errors_max_connections | 0 |
| Connection_errors_peer_address | 0 |
| Connection_errors_select | 0 |
| Connection_errors_tcpwrap | 0 |
| Connections | 9 |
| Created_tmp_disk_tables | 0 |
| Created_tmp_files | 6 |
| Created_tmp_tables | 5 |
| Delayed_errors | 0 |
| Delayed_insert_threads | 0 |
| Delayed_writes | 0 |
| Flush_commands | 1 |
| Handler_commit | 0 |
| Handler_delete | 0 |
| Handler_discover | 0 |
| Handler_external_lock | 0 |
| Handler_mrr_init | 0 |
| Handler_prepare | 0 |
| Handler_read_first | 0 |
| Handler_read_key | 0 |
| Handler_read_last | 0 |
| Handler_read_next | 0 |
| Handler_read_prev | 0 |
| Handler_read_rnd | 0 |
| Handler_read_rnd_next | 47 |
| Handler_rollback | 0 |
| Handler_savepoint | 0 |
| Handler_savepoint_rollback | 0 |
| Handler_update | 0 |
| Handler_write | 42 |
| Innodb_buffer_pool_dump_status | not started |
| Innodb_buffer_pool_load_status | not started |
| Innodb_buffer_pool_pages_data | 181 |
| Innodb_buffer_pool_bytes_data | 2965504 |
| Innodb_buffer_pool_pages_dirty | 0 |
| Innodb_buffer_pool_bytes_dirty | 0 |
| Innodb_buffer_pool_pages_flushed | 54 |
| Innodb_buffer_pool_pages_free | 8010 |
| Innodb_buffer_pool_pages_misc | 0 |
| Innodb_buffer_pool_pages_total | 8191 |
| Innodb_buffer_pool_read_ahead_rnd | 0 |
| Innodb_buffer_pool_read_ahead | 0 |
| Innodb_buffer_pool_read_ahead_evicted | 0 |
| Innodb_buffer_pool_read_requests | 944 |
| Innodb_buffer_pool_reads | 168 |
| Innodb_buffer_pool_wait_free | 0 |
| Innodb_buffer_pool_write_requests | 189 |
| Innodb_data_fsyncs | 38 |
| Innodb_data_pending_fsyncs | 0 |
| Innodb_data_pending_reads | 0 |
| Innodb_data_pending_writes | 0 |
| Innodb_data_read | 2822144 |
| Innodb_data_reads | 183 |
| Innodb_data_writes | 80 |
| Innodb_data_written | 1791488 |
| Innodb_dblwr_pages_written | 54 |
| Innodb_dblwr_writes | 4 |
| Innodb_have_atomic_builtins | ON |
| Innodb_log_waits | 0 |
| Innodb_log_write_requests | 31 |
| Innodb_log_writes | 11 |
| Innodb_os_log_fsyncs | 16 |
| Innodb_os_log_pending_fsyncs | 0 |
| Innodb_os_log_pending_writes | 0 |
| Innodb_os_log_written | 19456 |
| Innodb_page_size | 16384 |
| Innodb_pages_created | 14 |
| Innodb_pages_read | 167 |
| Innodb_pages_written | 54 |
| Innodb_row_lock_current_waits | 0 |
| Innodb_row_lock_time | 0 |
| Innodb_row_lock_time_avg | 0 |
| Innodb_row_lock_time_max | 0 |
| Innodb_row_lock_waits | 0 |
| Innodb_rows_deleted | 0 |
| Innodb_rows_inserted | 0 |
| Innodb_rows_read | 0 |
| Innodb_rows_updated | 0 |
| Innodb_num_open_files | 9 |
| Innodb_truncated_status_writes | 0 |
| Innodb_available_undo_logs | 128 |
| Key_blocks_not_flushed | 0 |
| Key_blocks_unused | 6698 |
| Key_blocks_used | 0 |
| Key_read_requests | 0 |
| Key_reads | 0 |
| Key_write_requests | 0 |
| Key_writes | 0 |
| Last_query_cost | 0.000000 |
| Last_query_partial_plans | 0 |
| Max_used_connections | 1 |
| Not_flushed_delayed_rows | 0 |
| Open_files | 46 |
| Open_streams | 0 |
| Open_table_definitions | 81 |
| Open_tables | 81 |
| Opened_files | 173 |
| Opened_table_definitions | 4 |
| Opened_tables | 2 |
| Performance_schema_accounts_lost | 0 |
| Performance_schema_cond_classes_lost | 0 |
| Performance_schema_cond_instances_lost | 0 |
| Performance_schema_digest_lost | 0 |
| Performance_schema_file_classes_lost | 0 |
| Performance_schema_file_handles_lost | 0 |
| Performance_schema_file_instances_lost | 0 |
| Performance_schema_hosts_lost | 0 |
| Performance_schema_locker_lost | 0 |
| Performance_schema_mutex_classes_lost | 0 |
| Performance_schema_mutex_instances_lost | 0 |
| Performance_schema_rwlock_classes_lost | 0 |
| Performance_schema_rwlock_instances_lost | 0 |
| Performance_schema_session_connect_attrs_lost | 0 |
| Performance_schema_socket_classes_lost | 0 |
| Performance_schema_socket_instances_lost | 0 |
| Performance_schema_stage_classes_lost | 0 |
| Performance_schema_statement_classes_lost | 0 |
| Performance_schema_table_handles_lost | 0 |
| Performance_schema_table_instances_lost | 0 |
| Performance_schema_thread_classes_lost | 0 |
| Performance_schema_thread_instances_lost | 0 |
| Performance_schema_users_lost | 0 |
| Prepared_stmt_count | 0 |
| Qcache_free_blocks | 1 |
| Qcache_free_memory | 1031352 |
| Qcache_hits | 0 |
| Qcache_inserts | 0 |
| Qcache_lowmem_prunes | 0 |
| Qcache_not_cached | 19 |
| Qcache_queries_in_cache | 0 |
| Qcache_total_blocks | 1 |
| Queries | 107 |
| Questions | 52 |
| Select_full_join | 0 |
| Select_full_range_join | 0 |
| Select_range | 0 |
| Select_range_check | 0 |
| Select_scan | 5 |
| Slave_heartbeat_period | |
| Slave_last_heartbeat | |
| Slave_open_temp_tables | 0 |
| Slave_received_heartbeats | |
| Slave_retried_transactions | |
| Slave_running | OFF |
| Slow_launch_threads | 0 |
| Slow_queries | 0 |
| Sort_merge_passes | 0 |
| Sort_range | 0 |
| Sort_rows | 0 |
| Sort_scan | 0 |
| Ssl_accept_renegotiates | 0 |
| Ssl_accepts | 0 |
| Ssl_callback_cache_hits | 0 |
| Ssl_cipher | |
| Ssl_cipher_list | |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_ctx_verify_depth | 0 |
| Ssl_ctx_verify_mode | 0 |
| Ssl_default_timeout | 0 |
| Ssl_finished_accepts | 0 |
| Ssl_finished_connects | 0 |
| Ssl_server_not_after | |
| Ssl_server_not_before | |
| Ssl_session_cache_hits | 0 |
| Ssl_session_cache_misses | 0 |
| Ssl_session_cache_mode | NONE |
| Ssl_session_cache_overflows | 0 |
| Ssl_session_cache_size | 0 |
| Ssl_session_cache_timeouts | 0 |
| Ssl_sessions_reused | 0 |
| Ssl_used_session_cache_entries | 0 |
| Ssl_verify_depth | 0 |
| Ssl_verify_mode | 0 |
| Ssl_version | |
| Table_locks_immediate | 70 |
| Table_locks_waited | 0 |
| Table_open_cache_hits | 28 |
| Table_open_cache_misses | 2 |
| Table_open_cache_overflows | 0 |
| Tc_log_max_pages_used | 0 |
| Tc_log_page_size | 0 |
| Tc_log_page_waits | 0 |
| Threads_cached | 0 |
| Threads_connected | 1 |
| Threads_created | 1 |
| Threads_running | 1 |
| Uptime | 3038 |
| Uptime_since_flush_status | 3038 |
+-----------------------------------------------+-------------+
341 rows in set (0.00 sec)
mysql>
```
- 查看各參數 show variables; show variables like 'max_connect%';
```
mysql> show variables;
| version_compile_os | linux-glibc2.5 |
| wait_timeout | 28800 |
| warning_count | 0 |
+--------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
453 rows in set (0.00 sec)
mysql>
```
- 查看參數max_connect相關的
```
mysql> show variables like 'max_connect%';
+--------------------+-------+
| Variable_name | Value |
+--------------------+-------+
| max_connect_errors | 100 |
| max_connections | 151 |
+--------------------+-------+
2 rows in set (0.00 sec)
mysql>
```
- 還可以查看slow相關的
```
mysql> show variables like 'slow%';
+---------------------+--------------------------------+
| Variable_name | Value |
+---------------------+--------------------------------+
| slow_launch_time | 2 |
| slow_query_log | OFF |
| slow_query_log_file | /data/mysql/localhost-slow.log |
+---------------------+--------------------------------+
3 rows in set (0.00 sec)
mysql>
```
- 修改參數 當然你也可以在/etc/my.cnf通過修改配置文件修改它，也可以在命令行裏面讓它在內存中生效 比如這個命令，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 (0.01 sec)
mysql>
```
- 如果你想重啓後還是1000，可以修改配置文件/etc/my.cnf,先要退出mysql，在這裏面定義max_connect_errors=1000; 再重啓就生效了
```
mysql> quit
Bye
[root@localhost ~]#
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d
~
~
"/etc/my.cnf" 19L, 560C
```
- 查看隊列 show processlist ; show full processlist;
-
```
[root@localhost ~]# mysql -uroot -paminglinux
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 10
Server version: 5.6.36 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, 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> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------+------------------+
| 10 | root | localhost | NULL | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.00 sec)
mysql>
mysql> show full processlist;
+----+------+-----------+------+---------+------+-------+-----------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------+-----------------------+
| 10 | root | localhost | NULL | Query | 0 | init | show full processlist |
+----+------+-----------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)
mysql>
```
- 查看隊列 show processlist ; 只顯示一部分info 最後一列， 好比在linux裏面 使用ps top去查看
- show full processlist;info 最後一列，顯示完整的隊列
- 擴展
- mysql5.7 root密碼更改 http://www.apelearn.com/bbs/thread-7289-1-1.html
mysql5.7之root密碼更改
mysql5.7root有默認密碼，必須重設密碼後，才能進行mysql的操作，以下是設置root密碼的步驟：
一、查看默認密碼
```
[root@localhost src]# cat /root/.mysql_secret
# The random password set for the root userat Fri Jan 10 20:00:34 2014 (local time): aJqZsA2m
這裏的aJqZsA2m就是生成的root隨機密碼啦
二、登錄mysql
[root@localhost src]# mysql -u root -p
Enter password:
```
輸入上面的密碼aJqZsA2m登錄，如果你沒有把mysql的路徑加到path裏，那就用絕對路徑，mysql -u root -p還可以寫成mysql -uroot -paJqZsA2m
三、更改密碼
mysql> SET PASSWORD FOR 'root'@localhost = PASSWORD（'123456'）；
Query OK, 0 rows affected (0.17 sec)
至此，就成功地修改了密碼。
如果出現問題，參考一下 http://www.apelearn.com/bbs/thread-10105-1-1.html 下面有更改root密碼的操作。
- myisam 和innodb引擎對比 http://www.pureweber.com/article/myisam-vs-innodb/
- mysql 配置詳解： http://blog.linuxeye.com/379.html
- mysql調優： http://www.aminglinux.com/bbs/thread-5758-1-1.html
- 同學分享的親身mysql調優經歷： http://www.apelearn.com/bbs/thread-11281-1-1.html13.1 設置更改root密碼 - 13.2 連接mysql - 13.3 mysql常用命令
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