MySQL does not generating PID file I upgraded my OS from redhat 2.6.3 to 2.6.5 after that
when I restarted my MySQL server but it not started,

error message is "150320 11:53:17 [ERROR] Error message file '/usr/share/mysql/english/errmsg.sys' had only 641 error messages,
but it should contain at least 728 error messages." and when I fired the command service mysql start it giving error "Starting MySQL......The server quit without updating PID file (/var/mysql-data/hostname.pid).                                            [FAILED]"

Please help..
I got the sollution,

1:extract your new mysql file :-
tar -zxf mysql-5.1.58.tar.gz

2:Rename the old errmsg.sys file which is in error file showing
mv /usr/share/mysql/english/errmsg.sys /usr/share/mysql/english/errmsg.sys.old

3:copy the new errmsg.sys file to exsting place
cp mysql-5.1.58/sql/share/english/errmsg.sys /usr/share/mysql/english/errmsg.sys

4:start your server.
 service mysql start

for Detail explanation kindly refer this link

http://toastergremlin.com/?p=447