当我试图运行/usr/bin/mysqltest,我遇到了下面的错误'/usr/bin/mysqltest: Failed in mysql_real_connect(): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2).' 我如何解决这个错误?
解决方法:

确保你的mysql-server软件包已经安装.使用下面的命令验证:

rpm -q mysql-server

这将输出安装了什么版本或者告诉你软件包没有被安装:

 
# rpm -q mysql-server
mysql-server-3.23.58-1

# rpm -q mysql-server
package mysql-server is not installed

对于红帽企业版Linux 3,mysql-server在红帽网络(RHN)的额外频道.只要额外频道在RHN中被一个注册的系统订阅就可以通过up2date命令安装.使用下面的命令从RHN上安装mysql-server软件包:

# up2date mysql-server

结果应该和下面的类似:

 
# up2date mysql-server
 
Fetching package list for channel: rhel-i386-as-3...
########################################
 
Fetching package list for channel: rhel-i386-as-3-extras...
########################################
 
Fetching Obsoletes list for channel: rhel-i386-as-3...
########################################
 
Fetching Obsoletes list for channel: rhel-i386-as-3-extras...

 
Fetching rpm headers...
########################################
 
Name                     Version        Rel
----------------------------------------------------------
mysql-server             3.23.58        1                 i386
 
 
Testing package set / solving RPM inter-dependencies...
########################################
mysql-server-3.23.58-1.i386 ########################## Done.
Preparing              ########################################### [100%]
 
Installing...
   1:mysql-server           ########################################### [100%]

把服务打开,为了在系统启动时把服务打开,可以执行chkconfig mysqld on命令。下面是一个例子:

 
# service mysqld start
Initializing MySQL database:                               [  OK  ]

# chkconfig --list mysqld
mysqld          0:off   1:off   2:off   3:off   4:off   5:off   6:off
# chkconfig mysqld on
# chkconfig --list mysqld
mysqld          0:off   1:off   2:on    3:on    4:on    5:on    6:off

如果服务被停止或者没有运行,可以执行/usr/bin/mysqltest命令,执行结果类似于:

 
# /usr/bin/mysqltest
/usr/bin/mysqltest: Failed in mysql_real_connect(): Can't connect to local
MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

一旦mysqld服务启动,这个失败的错误就不会在出现.