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).