MYSQL简介

查看mysql简介

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实验环境

安装步骤

• 下载安装包

  [root@localhost ~]# wget https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz
  --2021-04-18 20:58:11--  https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz
  Resolving downloads.mysql.com (downloads.mysql.com)... 137.254.60.14
  Connecting to downloads.mysql.com (downloads.mysql.com)|137.254.60.14|:443... connected.
  HTTP request sent, awaiting response... 302 Found
  Location: https://cdn.mysql.com/archives/mysql-5.7/mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz [following]
  --2021-04-18 20:58:12--  https://cdn.mysql.com/archives/mysql-5.7/mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz
  Resolving cdn.mysql.com (cdn.mysql.com)... 184.86.92.235
  Connecting to cdn.mysql.com (cdn.mysql.com)|184.86.92.235|:443... connected.
  HTTP request sent, awaiting response... 200 OK
  Length: 641127384 (611M) [application/x-tar-gz]
  Saving to: ‘mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz’
  
  100%[===================================================================>] 641,127,384 10.5MB/s   in 61s    
  
  2021-04-18 20:59:13 (10.1 MB/s) - ‘mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz’ saved [641127384/641127384]
  
  [root@localhost ~]# ls
  anaconda-ks.cfg  back_yum  he.txt  mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz
  
  

• 解压 安装包

  [root@localhost ~]# mv mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz /usr/local/
  [root@localhost local]# tar xf mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz 
  [root@localhost local]# ln -s mysql-5.7.20-linux-glibc2.12-x86_64/  mysql
  [root@localhost local]# ll mysql
  
  

• 创建用户

  [root@localhost local]# useradd -M -s /sbin/nologin mysql
  

• 修改目录/usr/local/mysql的属主属组

  [root@localhost local]# chown -R mysql:mysql mysql
  [root@localhost local]# ll mysql
  lrwxrwxrwx 1 mysql mysql 36 Apr 18 21:22 mysql -> mysql-5.7.20-linux-glibc2.12-x86_64/
  [root@localhost local]# 
  

• 设置环境变量

  [root@localhost bin]# echo 'export PATH=/usr/local/mysql/bin:$PATH' > /etc/profile.d/mysql.sh
  
  [root@localhost bin]# source /etc/profile.d/mysql.sh
  
  [root@localhost bin]# echo $PATH
  /usr/local/mysql/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
  

• 建立数据存放目录，并修改权限

  [root@localhost bin]# mkdir -p /data/mysql
  [root@localhost bin]# chown -R mysql.mysql /data/mysql/
  [root@localhost bin]# 
  

• 初始化数据库

  [root@localhost bin]# /usr/local/mysql/bin/mysqld --initialize --user=mysql --datadir=/data/mysql/ 
  2021-04-18T13:31:12.749412Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
  2021-04-18T13:31:13.310688Z 0 [Warning] InnoDB: New log files created, LSN=45790
  2021-04-18T13:31:13.376643Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
  2021-04-18T13:31:13.437436Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 584ca535-a04a-11eb-bee7-000c29e5f134.
  2021-04-18T13:31:13.438276Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
  2021-04-18T13:31:13.439087Z 1 [Note] A temporary password is generated for root@localhost: !4wowa:8MipQ
  [root@localhost bin]# 
  请注意，这个命令的最后会生成一个临时密码，此处密码是!4wowa:8MipQ。每个人初始化密码不一样，后面初次登陆用
  

• 创建mysql配置文件

  [root@localhost bin]# cat > /etc/my.cnf <<EOF
  > [mysqld]
  > basedir=/usr/local/mysql
  > datadir=/data/mysql/
  > socket=/tmp/mysql.sock
  > port=3306
  > pid-file=/data/mysql/mysql.pid
  > user=mysql
  > skip-name-resolve
  > EOF
  
  [root@localhost bin]# cat /etc/my.cnf
  [mysqld]
  basedir=/usr/local/mysql
  datadir=/data/mysql/
  socket=/tmp/mysql.sock
  port=3306
  pid-file=/data/mysql/mysql.pid
  user=mysql
  skip-name-resolve
  [root@localhost bin]# 
  
  

• 设置服务启动脚本

  [root@localhost bin]# cd ../support-files/
  [root@localhost support-files]# \cp -af mysql.server /etc/init.d/mysqld
  root@localhost support-files]# sed -ri 's#^(basedir=).*#\1/usr/local/mysql#g' /etc/init.d/mysqld
  [root@localhost support-files]# sed -ri 's#^(datadir=).*#\1/data/mysql/#g' /etc/init.d/mysqld
  

• 启动mysql

  [root@localhost support-files]# 
  [root@localhost support-files]# /etc/init.d/mysqld start
  Starting MySQL. SUCCESS! 
  

• 测试：

  [root@localhost ~]# ss -lant|grep 3306
  LISTEN     0      80          :::3306                    :::*                  
  [root@localhost ~]# mysql -uroot -p
  Enter password: 
  
  mysql> quit
  Bye
  [root@localhost ~]# 
  

总结

mysql常用配置文件参数

常见mysql 启动报错总结

- **报错1**

[root@localhost support-files]# /etc/init.d/mysqld start
Starting MySQL... ERROR! The server quit without updating PID file (/data/mysql/mysql.pid).
[root@localhost support-files]# 
关于网上对这个错误的总结，很多人都说权限问题，其实不管我们怎么给权限，好像都报错，很多时候都是因为配置文件有问题，才导致的，如果出现此错误，建议检查配置文件

- **报错2**

Systemctl restart mariadb.service
Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe" for details.
解决方法：查看错误日志：journalctl –xe

查看端口是否被占用：netstat -tnlp|grep 3306

最终的判断，MYSQL进程已经存在，无法启动Mariadb，解决方法，停止原来的MYSQL服务；

- **报错3**

Redirecting to /bin/systemctl restart  mariadb.service
Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe" for details.
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)解决方法：

使用journalctl –xe查看MYSQL错误信息；
关闭服务器selinux安全策略，关闭防火墙setenforce 0；
检查MYSQL|Mariadb通过什么样的方式部署的；
检查其配置文件/etc/my.cnf，datadir数据目录是否配置；检查socket是否配置正确
确认数据库的数据目录mysql用户是否拥有读写权限；
检查数据库目录是否初始化，是否包括mysql、test基础库；
检查socket文件所在的路径，是否存在socket文件，权限是否正确；