What & How & Why

这是本文档旧的修订版！

[mysql-generic-5.5.40 restart]
=============================================================
mysql-generic-5.5.40
[OK] mysql-generic-5.5.40 is already installed.
>ERROR! MySQL server PID file could not be found!
>Starting MySQL. ERROR! The server quit without updating PID file 
>(/home/usrdata/mysql-generic-5.5.40/mysql.pid).