系统mac 10.14.3
安装: brew install mysql
问题1：mysql服务起不来
1.1 报错：
ERROR! The server quit without updating PID file(/usr/local/var/mysql/MAC-OF-BPDJ-ZP.local.pid
1.2 解决：
重新命名数据文件 mv /usr/local/var/mysql /usr/local/var/mysql_bak
1.3 具体操作如下
1.启动 mysql
➜ support-files sudo /usr/local/Cellar/mysql/8.0.17/support-files/mysql_server start
Starting MySQL
....... ERROR! The server quit without updating PID file (/usr/local/var/mysql/MAC-OF-BPDJ-ZP.local.pid).
2.报错
/usr/local/var/mysql
/usr/local/Cellar/mysql/8.0.17/support-files/mysql.server start
3.删除 rm mysql-bin.000001 - rm mysql-bin.000011
4.直接重命名文件夹 mv /usr/local/var/mysql /usr/local/var/mysql_bak
5.卸载mysql: brew uninstall mysql
➜ var brew uninstall mysql
Uninstalling /usr/local/Cellar/mysql/8.0.17... (284 files, 272.5MB)
6.重新安装mysql: brew install mysql
➜ local brew install mysql
Updating Homebrew...
Ignoring path homebrew-cask/
To restore the stashed changes to /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask run:
'cd /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask && git stash pop'
==> Auto-updated Homebrew!
Updated 2 taps (homebrew/core and homebrew/cask).
==> Updated Formulae
libpq ✔ libpqxx postgresql@10 [email protected] tor
jenkins postgresql [email protected] rke ucloud
==> Downloading https://homebrew.bintray.com/bottles/mysql-8.0.17.mojave.bottle.tar.gz
Already downloaded: /Users/b_tt/Library/Caches/Homebrew/downloads/45d08ca8020b5abe52a5de9fb782dae5f34e6790f9664049b863fd02a404f947--mysql-8.0.17.mojave.bottle.tar.gz
==> Pouring mysql-8.0.17.mojave.bottle.tar.gz
==> /usr/local/Cellar/mysql/8.0.17/bin/mysqld --initialize-insecure --user=b_tt --basedir
Warning: The post-install step did not complete successfully
You can try again using `brew postinstall mysql`
==> Caveats
We've installed your MySQL database without a root password. To secure it run:
mysql_secure_installation
MySQL is configured to only allow connections from localhost by default
To connect run:
mysql -uroot
A "/etc/my.cnf" from another install may interfere with a Homebrew-built
server starting up correctly.
To have launchd start mysql now and restart at login:
brew services start mysql
Or, if you don't want/need a background service you can just run:
mysql.server start
==> Summary
/usr/local/Cellar/mysql/8.0.17: 284 files, 272.5MB
7.查看mysql配置文件在哪里：mysql --help|grep 'my.cnf'
➜ /etc mysql --help|grep 'my.cnf'
order of preference, my.cnf, $MYSQL_TCP_PORT,
/etc/my.cnf /etc/mysql/my.cnf /usr/local/etc/my.cnf ~/.my.cnf
8.查看mysql:brew info mysql
1.4 参考文章 https://cloud.tencent.com/developer/article/1339287
问题2 MySQL 启动成功但未监听3306
2.1 现象：ps aux | grep mysql有进程，lsof -i -n -P | grep :3306没有监听3306端口
➜ mysql ps aux | grep mysql
b_tt 8535 0.0 0.0 4277236 540 s002 R+ 3:06下午 0:00.00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn mysql
b_tt 8364 0.0 3.9 4802876 327176 ?? S 2:58下午 0:01.93 /usr/local/opt/mysql/bin/mysqld --basedir=/usr/local/opt/mysql --datadir=/usr/local/var/mysql --plugin-dir=/usr/local/opt/mysql/lib/plugin --log-error=MAC-OF-BPDJ-ZP.local.err --pid-file=MAC-OF-BPDJ-ZP.local.pid --socket=/tmp/mysql.sock --port=3307
b_tt 8073 0.0 0.0 4279864 1236 ?? S 2:58下午 0:00.05 /bin/sh /usr/local/opt/mysql/bin/mysqld_safe --datadir=/usr/local/var/mysql
➜ mysql lsof -i -n -P | grep :3306
2.2 解决 注释掉配置文件的 skip-grant-tables和skip-networking两个选项，重启服务
2.3 参考文档https://dev.mysql.com/doc/refman/8.0/en/resetting-permissions.html
官方手册有这样的一句话：
如有必要，请停止MySQL服务器，然后使用该--skip-grant-tables 选项重新启动它
这使得任何人都可以在没有密码和所有权限的情况下进行连接，
并禁用帐户管理语句，例如 ALTER USER和 SET PASSWORD。
因为这是不安全的，如果使用该--skip-grant-tables 选项启动服务器 ，
它会--skip-networking 自动启用 以防止远程连接。
PS:说明 开启 skip-grant-tables 会自动启用skip-networking
问题3 命令行可以登录(mysql -u root -p),但是客户端sequel pro登录不了
3.1 设置root密码
3.2 解决
B.4.3.2.3重置Root密码：通用指令
前面几节提供了专门针对Windows和Unix以及类Unix系统的密码重置说明。或者，在任何平台上，您都可以使用mysql客户端重置密码（但这种方法不太安全）：
1.如有必要，请停止MySQL服务器，然后使用该--skip-grant-tables 选项重新启动它。这使得任何人都可以在没有密码和所有权限的情况下进行连接，并禁用帐户管理语句，例如 ALTER USER和 SET PASSWORD。因为这是不安全的，如果使用该--skip-grant-tables 选项启动服务器 ，它会--skip-networking 自动启用 以防止远程连接。
启动服务：
shell> /usr/local/opt/mysql/bin/mysql.server start --skip-grant-tables
2.使用mysql客户端连接MySQL服务器 ; 没有密码是必需的，因为服务器启动时 --skip-grant-tables：
shell> mysql
3.在mysql客户端中，告诉服务器重新加载授权表，以便帐户管理语句起作用：
mysql> FLUSH PRIVILEGES;
4.然后更改'root'@'localhost' 帐户密码。将密码替换为您要使用的密码。要更改root具有不同主机名部分的帐户的密码 ，请修改使用该主机名的说明。
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
您现在应该能够root使用新密码连接到MySQL服务器 。停止服务器并正常重新启动它（没有 --skip-grant-tables和 --skip-networking选项）。
到此为止 命令行可以用 mysql -u root -p root登录(原来的密码是空)
3.3 参考官方手册：[https://dev.mysql.com/doc/refman/8.0/en/resetting-permissions.html](https://dev.mysql.com/doc/refman/8.0/en/resetting-permissions.html
3.4 客户端sequal pro依然登录不上去 报错Authentication plugin 'caching_sha2_password' cannot be loaded: dlopen(/usr/local/lib/plugin...
3.5 解决 ALTER USER root@localhost IDENTIFIED WITH mysql_native_password BY '用户root的登录密码';
➜ /etc mysql -u root -p root
Enter password: root
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 8.0.17 Homebrew
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Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use mysql
Database changed
mysql> select user,host,plugin from user;
+------------------+-----------+-----------------------+
| user | host | plugin |
+------------------+-----------+-----------------------+
| mysql.infoschema | localhost | caching_sha2_password |
| mysql.session | localhost | caching_sha2_password |
| mysql.sys | localhost | caching_sha2_password |
| root | localhost | caching_sha2_password |
+------------------+-----------+-----------------------+
4 rows in set (0.00 sec)
mysql>
mysql> ALTER USER root@localhost IDENTIFIED WITH mysql_native_password BY 'root';
Query OK, 0 rows affected (0.01 sec)
mysql> select user,host,plugin from user;
+------------------+-----------+-----------------------+
| user | host | plugin |
+------------------+-----------+-----------------------+
| mysql.infoschema | localhost | caching_sha2_password |
| mysql.session | localhost | caching_sha2_password |
| mysql.sys | localhost | caching_sha2_password |
| root | localhost | mysql_native_password |
+------------------+-----------+-----------------------+
4 rows in set (0.00 sec)