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第 47 章 FAQ


47.1. Reset root password 重置MySQL root密码
47.1.1. MySQL 5.7.x
47.1.2. MySQL 8.0
47.2. 数据库内容替换
47.3. 查看错误代码
47.3.1. ERROR 1153 (08S01) at line 3168: Got a packet bigger than 'max_allowed_packet' bytes
47.3.2. ERROR 1129 (00000): Host 'XXXXXX' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'
47.4. 临时表是否需要建索引
47.5. Kill 脚本
47.6. ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function
47.7. ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
47.8. ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
47.9. 重新整理AUTO_INCREMENT字段
47.10. 转换 latin1 到 UTF-8
47.11. this is incompatible with sql_mode=only_full_group_by
47.12. [Warning] Changed limits: max_open_files: 5000 (requested 20480)
47.13. ERROR 1364: 1364: Field 'id' doesn't have a default value
47.14. ERROR 1290 (HY000): The MySQL server is running with the --secure-file-priv option so it cannot execute this statement
47.15. ERROR 1086 (HY000): File '/var/lib/mysql-files/order.txt' already exists
47.16. ERROR 1415: Not allowed to return a result set from a trigger
47.17. Authentication plugin 'caching_sha2_password' cannot be loaded: /usr/lib64/mysql/plugin/caching_sha2_password.so: cannot open shared object file: No such fileor directory
47.18. com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Public Key Retrieval is not allowed

47.1. Reset root password 重置MySQL root密码

忘记root密码是使用 --skip-grant-tables 启动项

CentOS 6.x

# vim /etc/init.d/mysqld

 $exec --skip-grant-tables  --datadir="$datadir" --socket="$socketfile" \
    --pid-file="$mypidfile" \
    --basedir=/usr --user=mysql >/dev/null 2>&1 &
# /etc/init.d/mysqld restart
Stopping mysqld:                                           [  OK  ]
Starting mysqld:                                           [  OK  ]

# mysqladmin -u root flush-privileges password "newpassword"

47.1.1. MySQL 5.7.x

CentOS 7.x

添加 skip-grant-tables=1 选项,然后重启mysql

# cat /etc/my.cnf
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
# Disabling symbolic-links is recommended to prevent assorted security risks

# Recommended in standard MySQL setup

# systemctl restart mysqld
update mysql.user set authentication_string=password('netkiller') where user='root' and Host = 'localhost';
flush privileges;
# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.14 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, 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

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> update mysql.user set authentication_string=password('netkiller') where user='root' and Host = 'localhost';
Query OK, 1 row affected, 1 warning (0.03 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> quit;

删除 skip-grant-tables=1 重启MySQL

47.1.2. MySQL 8.0

[root@localhost log]# vim /etc/my.cnf

ALTER USER root@localhost identified by 'MQiEge1ikst7S_6tlXzBOmt';