mysql（linux下）bug集结

Mysql

启动测试：

# systemctl status mysqld.service

 

 

查看日志：

tail -n 200  /var/log/mysqld.log

 

2018-08-10T02:24:04.877063Z 0 [Warning] Can't create test file /data/mysql/VM_129_126_centos.lower-test

 

2018-08-10T02:24:04.906042Z 0 [ERROR] InnoDB: The innodb_system data file 'ibdata1' must be writable

 

日志

 

设置权限：

[root@VM_129_126_centos mysql]# sudo chmod 777 /data/mysql/

再次测试：

 

 

 

 

重启：

mysqld restart --user=root

 

 

 

 

 

 =================================================================================

 

 

 

 

 

 

 

create database jnshu default charset utf8;

 

停止

service mysqld stop

启动服务

service mysqld start

重启

service mysqld restart

 

mysqld --initialize --user=root

mysqld --user=root

mysqld restart --user=root

 

mysqld --skip-grant-tables

 

重启服务器

 

"jdbc:mysql://119.29.17.188/jnshu?useUnicode=true&characterEncoding=UTF-8&useSSL=false&rewriteBatchedStatements=true";

 

日志：

vim /var/log/mysqld.log

tail -n 100 /var/log/mysqld.log  

Packet for query is too large (12238 > 1024). You can change this value

 

show VARIABLES like '%max_allowed_packet%';

 

set global max_allowed_packet = 2*1024*1024*10

 

 

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111)

ERROR 2003 (HY000): Can't connect to MySQL server on '127.0.0.1' (111)

 

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111)

 

 

删除 /var/lib/mysql/mysql.sock

重新mysql -uroot -p

 

提示：

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

 

停止

service mysqld stop

 

启动服务

service mysqld start

 

提示：

Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details

 

使用：

mysqld --user=root

 

重新连接

 

 

 

 

 

查看：

systemctl status mysqld.service

 

 

 

journalctl -xe

 

 

 

 

Can't create test file /data/mysql/VM_129_126_centos.lower-test

 

 

 

 

vi /etc/selinux/config

 

摘抄：

下面为转：

本文永久更新链接地址：http://www.linuxidc.com/Linux/2016-11/137723.htm

1. 查看SELinux状态

1.1 getenforce

• getenforce 命令是单词get（获取）和enforce(执行)连写，可查看selinux状态，与setenforce命令相反。
• setenforce 命令则是单词set（设置）和enforce(执行)连写，用于设置selinux防火墙状态，如： setenforce 0用于关闭selinux防火墙，但重启后失效
  [root@localhost ~]# getenforce
  Enforcing

1.2 /usr/sbin/sestatus

Current mode表示当前selinux防火墙的安全策略

[root@localhost ~]# /usr/sbin/sestatus

SELinux status: enabled

SELinuxfs mount: /sys/fs/selinux

SELinux root directory: /etc/selinux

Loaded policy name: targeted

Current mode: enforcing

Mode from config file: enforcing

Policy MLS status: enabled

Policy deny_unknown status: allowed

Max kernel policy version: 28

SELinux status：selinux防火墙的状态，enabled表示启用selinux防火墙

Current mode： selinux防火墙当前的安全策略，enforcing 表示强

2. 关闭SELinux

2.1 临时关闭

setenforce 0 ：用于关闭selinux防火墙，但重启后失效。

[root@localhost ~]# setenforce 0

[root@localhost ~]# /usr/sbin/sestatus

SELinux status: enabled

SELinuxfs mount: /sys/fs/selinux

SELinux root directory: /etc/selinux

Loaded policy name: targeted

Current mode: permissive

Mode from config file: enforcing

Policy MLS status: enabled

Policy deny_unknown status: allowed

Max kernel policy version: 28

2.1 永久关闭

修改selinux的配置文件，重启后生效。

打开 selinux 配置文件

[root@localhost ~]# vim /etc/selinux/config

修改 selinux 配置文件

将SELINUX=enforcing改为SELINUX=disabled，保存后退出

# This file controls the state of SELinux on the system.# SELINUX= can take one of these three values:# enforcing - SELinux security policy is enforced.# permissive - SELinux prints warnings instead of enforcing.# disabled - No SELinux policy is loaded.SELINUX=enforcing

# SELINUXTYPE= can take one of three two values:# targeted - Targeted processes are protected,# minimum - Modification of targeted policy. Only selected processes are protected. # mls - Multi Level Security protection.SELINUXTYPE=targeted

此时获取当前selinux防火墙的安全策略仍为Enforcing，配置文件并未生效。

[root@localhost ~]# getenforce

Enforcing

重启

[root@localhost ~]# reboot

验证

[root@localhost ~]# /usr/sbin/sestatus

SELinux status: disabled

 

[root@localhost ~]# getenforce

Disabled