错误描述：
在yum安装软件的过程中使用 Ctrl + c 组合键取消安装,之后再使用yum时报错：
Error: database disk p_w_picpath is malformed
例如：
[test@localhost etc]$ yum repolist
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base: mirrors.yun-idc.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
Error: database disk p_w_picpath is malformed
解决方法：
以root用户执行 yum clean dbcache
×××××××××××××××××××××××××××××××××××××××××××××
1.测试使用普通用户执行 yum clean dbcache 命令无效
[test@localhost etc]$ yum clean dbcache
Loaded plugins: fastestmirror, security
Cleaning repos: base extras updates
4 sqlite files removed
[test@localhost etc]$ yum repolist
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base: mirrors.yun-idc.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
Error: database disk p_w_picpath is malformed
2.测试使用sudo无效
[test@localhost etc]$ sudo yum clean dbcache
[sudo] password for test:
Loaded plugins: fastestmirror, security
Cleaning repos: base extras updates
5 sqlite files removed
[test@localhost etc]$ yum repolist
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base: mirrors.yun-idc.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
Error: database disk p_w_picpath is malformed
3.切换到root用户再执行，成功
[test@localhost etc]$ su -
Password:
[root@localhost ~]# yum clean dbcache
Loaded plugins: fastestmirror, security
Cleaning repos: base extras updates
0 sqlite files removed
[root@localhost ~]# yum repolist
Loaded plugins: fastestmirror, security
Determining fastest mirrors
* base: mirrors.yun-idc.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
base/primary_db | 4.6 MB 00:09
extras/primary_db | 37 kB 00:00
updates/primary_db | 5.2 MB 00:11
repo id repo name status
base CentOS-6 - Base 6,575
extras CentOS-6 - Extras 62
updates CentOS-6 - Updates 1,622
repolist: 8，259
[root@localhost ~]#