mysql版本升级 5.7.21-8.0.30

当前MySQL版本为：5.7.21

升级前准备，了解5.7和8.0版本有何区别，本文主要为升级操作文档，具体建议参考官方文档，概括性的有以下几点：

》默认字符集由latin1变为utf8mb4

》支持隐藏索引，索引可以被隐藏和显示

》用户创建，修改和授权

》sql_mode参数默认值变化

》支持窗口函数等

》sql_mode参数默认值变化

以下为升级8.0需要配置文件中新增的参数配置

#for8.0
sql_mode = STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION
character-set-server = utf8mb4
collation_server = utf8mb4_general_ci
basedir = /home/mysql8
skip_ssl
default_authentication_plugin=mysql_native_password

环境说明：我是本机部署了两个mysql 实例，分别为3306和3307，3306为主节点

首先升级实例3307 （从库）

[root@localhost mysql]# ./bin/mysql -uroot -p -S /home/mysql/3307/mysql.sock
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.21-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> show variables like 'innodb_fast_shutdown';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| innodb_fast_shutdown | 1     |
+----------------------+-------+
1 row in set (0.01 sec)

mysql> set global innodb_fast_shutdown=0;
Query OK, 0 rows affected (0.00 sec)

mysql> shutdown;

mysql> exit
Bye

[root@localhost mysql8]# cd /home/mysql8
[root@localhost mysql8]# ./bin/mysqld_safe --defaults-file=/home/mysql/3307/my.cnf &

登录重新查看版本以及主从情况和数据

[root@localhost mysql]# ./bin/mysql -uroot -p -S /home/mysql/3307/mysql.sock
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 8.0.30 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 version();
+-----------+
| version() |
+-----------+
| 8.0.30    |
+-----------+
1 row in set (0.01 sec)

mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.53.123
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000007
          Read_Master_Log_Pos: 154
               Relay_Log_File: relay-log.000011
                Relay_Log_Pos: 370
        Relay_Master_Log_File: mysql-bin.000007
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
... ...

升级完成，3306实例主库操作同上

升级过程错误汇总：

1、启动失败，提示信息如下

经对 msyqld_safe 启动文件查看发现变量MY_PWD=`pwd`，执行启动得时候不能使用绝对路径，此变量需要获取当前路径，先进入mysql8 目录下执行./msyqld_safe --defaults-file="配置文件" 及恢复正常

如下信息说明现在启动后得配置文件使用得即为指定得配置文件

2、启动报错，日志如下图，此报错说设置utf8_general_ci设置utf8mb4，修改配置文件

3、启动报错，根据日志错误提示mysql5.7.21不支持innodb_dast_shutdown = 2 得时候升级