MySQL 5.7升级到8.0详细过程_mysql5.7升级8.0步骤

一、升级前准备

1.1.MySQL提供mysql-shell验证方式，可以下载后进行验证：

下载shell验证文件：
        https://cdn.mysql.com/archives/mysql-shell/mysql-shell-8.0.27-linux-glibc2.12-x86-64bit.tar.gz

         验证是否可以升级成功（验证的时候出现了几个错误没去处理，升级后倒时也没发现问题，如果是生产环境下还是要小心一些）

# 验证mysql升级
[root@localhost] tar -xf mysql-shell-8.0.27-linux-glibc2.12-x86-64bit.tar.gz
[root@localhost] cd mysql-shell-8.0.27-linux-glibc2.12-x86-64bit/bin
[root@localhost] ./mysqlsh -uroot -p'123456' -S /tmp/mysql.sock -e "util.checkForServerUpgrade()"

   1.2. 备份原数据库（防止升级过程中出现问题，导致数据丢失，有条件建议异地备份）    

[root@localhost] mysqldump -uroot -p'123456' --all-databases  --lock-tables=0 > all.sql.bak.20220412
[root@localhost] mv all.sql.bak.20220412 /data/backup/mysql/

1.3.下载MySQL8.0

​拉取软件包
[root@localhost] wget https://downloads.mysql.com/archives/get/p/23/file/mysql-8.0.21-1.el7.x86_64.rpm-bundle.tar
 
# 解压mysql8.0
[root@localhost] tar zxvf mysql-8.0.21-el7-x86_64.tar.gz -C ../server/mysql3306/
 
# 移动到指定目录
[root@localhost] mv mysql-8.0.21-el7-x86_64 /usr/local/mysql8
 
# 更改文件夹所属
[root@localhost] chown -R mysql.mysql /usr/local/mysql8/

二、升级过程配置

2.1. 修改mysql配置文件，主要是mysql8.0部分，及sql_mode中的NO_ENGINE_SUBSTITUTION

# 编辑配置文件
[root@localhost] vim /etc/my.cnf
 
[client]
port=3306
socket=/tmp/mysql.sock
 
[mysqld]
log-bin=mysql-bin
server-id=170
character_set_server=utf8
init_connect='SET NAMES utf8'
#basedir=/usr/local/mysql
#datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
log-error=/var/log/mysqld.log
pid-file=/run/mysqld/mysqld.pid
#不区分大小写
lower_case_table_names =1
 
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION
 
max_connections=5000
 
default-time_zone = '+8:00'
max_allowed_packet = 32M
#default_password_lifetime=90
#wait_timeout=600
 
# mysql8.0 add
collation-server=utf8_general_ci
basedir=/usr/local/mysql8
datadir=/usr/local/mysql/data
skip_ssl
default_authentication_plugin=mysql_native_password

2.2 开始升级

# 进入原mysql命令行
[root@localhost] mysql -uroot -p'123456'
 
# 查看mysql版本
mysql> select version();
+------------+
| version()  |
+------------+
| 5.7.26-log |
+------------+
1 row in set (0.00 sec)
 
mysql> show variables like 'innodb_fast_shutdown';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| innodb_fast_shutdown | 1     |
+----------------------+-------+
1 row in set (0.00 sec)
 
# 确保数据都刷到硬盘上，更改成0
mysql> set global innodb_fast_shutdown=0;
Query OK, 0 rows affected (0.00 sec)
 
mysql> shutdown;
Query OK, 0 rows affected (0.00 sec)
 
mysql> exit;
Bye

2.3 使用安全模式启动mysql8.0，正常启动后可以进入到mysql命令行，如果没启动成功，需要查看日志cat /var/log/mysqld.log解决后，再进入命令行

# 使用mysql8.0启动
[root@localhost] /usr/local/mysql8/bin/mysqld_safe --defaults-file=/etc/my.cnf --user=mysql &
 
 
# 进入mysql命令行
[root@localhost] mysql -uroot -p'123456'
mysql> select version();
+-----------+
| version() |
+-----------+
| 8.0.27    |
+-----------+
1 row in set (0.00 sec)
 
mysql> exit;
Bye

2.4 配置环境变量

[root@localhost] vim /etc/profile
 
# add mysql
export PATH=$PATH:/usr/local/mysql8/bin
 
# 使环境变量生效
[root@localhost] source /etc/profile

2.5查看客户端版本配置

# 验证版本
[root@localhost] which mysql
/usr/local/mysql8/bin/mysql
# 查看版本
[root@localhost] mysql -V
mysql  Ver 8.0.27 for Linux on x86_64 (MySQL Community Server - GPL)

三、配置启动项

[root@localhost] cp /usr/local/mysql8/support-files/mysql.server /etc/init.d/mysqld
# 修改启动项目
[root@localhost] vim /etc/init.d/mysqld
# 修改目录位置
basedir=/usr/local/mysql8
datadir=/usr/local/mysql/data
 
# 添加到启动列表 
[root@localhost] chkconfig --add mysqld
# 刷新启动信息
[root@localhost] systemctl daemon-reload
# 查看启动项列表
[root@localhost] chkconfig --list

重新启动服务器没有成功，启动的时候报错没有mysqld.pid文件，创建后启动成功

# 重启动无法创建mysqld.pid文件处理方法
[root@localhost] cat /var/log/mysqld.log
[root@localhost] cd /run
[root@localhost] mkdir mysqld
[root@localhost] chown -R mysql.mysql ./mysqld
[root@localhost] cd mysqld
[root@localhost] touch mysqld.pid
[root@localhost] chown -R mysql.mysql ./mysqld.pid
[root@localhost] service mysqld start
 
Starting MySQL.. SUCCESS!