解决 Postfix 丢失共享库 libmysqlclient.so.18

解决这个奇怪的问题：

Postfix: error while loading shared libraries: libmysqlclient.so.16

[root@he moenet.net]# service postfix status
Redirecting to /bin/systemctl status postfix.service
● postfix.service – Postfix Mail Transport Agent
Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Wed 2017-03-22 18:50:50 CST; 29min ago

Mar 22 18:50:50 he.net systemd[1]: Starting Postfix Mail Transport Agent…
Mar 22 18:50:50 he.net aliasesdb[19231]: /usr/sbin/postconf: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
Mar 22 18:50:50 he.net aliasesdb[19231]: /usr/bin/newaliases: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
Mar 22 18:50:50 he.net postfix[19239]: /usr/sbin/postfix: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
Mar 22 18:50:50 he.net systemd[1]: postfix.service: control process exited, code=exited status=127
Mar 22 18:50:50 he.net systemd[1]: Failed to start Postfix Mail Transport Agent.
Mar 22 18:50:50 he.net systemd[1]: Unit postfix.service entered failed state.
Mar 22 18:50:50 he.net systemd[1]: postfix.service failed.

CentOS 7:

yum reinstall mysql-libs -y

好了，这样就搞定了。