centos8降级centos7安装mysql遇到的问题

luobiaodeMacBook-Air:~ luobiao$ ssh root@39.101.204.8

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!    @

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!

Someone could be eavesdropping on you right now (man-in-the-middle attack)!

It is also possible that a host key has just been changed.

The fingerprint for the ECDSA key sent by the remote host is

SHA256:jN2L7Ebd8ZV03ErBmMpGwHybqNBnLqOX0TTk9TbgzZs.

Please contact your system administrator.

Add correct host key in /Users/luobiao/.ssh/known_hosts to get rid of this message.

Offending ECDSA key in /Users/luobiao/.ssh/known_hosts:8

ECDSA host key for 39.101.204.8 has changed and you have requested strict checking.

Host key verification failed.

解决：

这里面，有一句很关键。

ECDSA host key for 39.101.204.8  has changed and you have requested strict checking.

Host key verification failed.

一般这个问题，是你重置过你的服务器后。你再次想访问会出现这个问题。

ssh-keygen -R  39.101.204.8 

1.安装mysql报错

mysqld: error while loading shared libraries: libaio.so.1: cannot open shared object file: No such file or directory

解决：

经过百度说是缺少 libaio.so.1  这个包.这个包是干什么的呢？

我也没查看到？试试先安装这个包。

yum -y install libaio  

安装后，解决该问题。

2.[ root @later01 /errlog ]# /etc/init.d/mysqld start 

Starting MySQL.2020-04-11T16:49:17.645735Z mysqld_safe error: log-error set to '/errlog/3306/mysql.log', however file don't exists. Create writable for user 'mysql'.

解决： 创建日志文件并赋权 

[ root @later01 /errlog/3306 ]# echo "" >mysql.log 

[ root @later01 /errlog/3306 ]# chown -R mysql.mysql /errlog/

3.2020-04-11T16:52:12.084460Z 0 [ERROR] InnoDB: The innodb_system data file './ibdata1' is of a different size 768 pages (rounded down to MB) than the 4864 pages specified in the .cnf file!

解决：注释my.cnf 中的

#innodb_data_file_path=ibdata1:76Mibdata2:100Mibdata3:100M:autoextend

window10专业版&&MySQL8.0

课程项目中使用MySQL做新指标构建时需要用到等值连接查询，并将结果存在新表中；

数据量较大（32,320,079条）情况下运行时出现 ERROR 1206 (HY000): The total number of locks exceeds the lock table size 。

数据量过大时会报错 ERROR 1206 (HY000): The total number of locks exceeds the lock table size

先查询 innodb_buffer_pool_size 的值

可以看到 innodb_buffer_pool_size 默认为8M，需要改大。

进入 C:\ProgramData\MySQL\MySQL Server 8.0 目录修改my.ini文件（管理员模式打开），找到 innodb_buffer_pool_size ，将默认值改为64M.

重新启动MySQL服务（在任务管理器中），再次试验后成功