MyTrueHost 
Posted in 
This issue usually happens after the mysql downgrade from version 5 to 4.
The error will be like:
ERROR 2002: Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)
If you check further, you can see charset issue related with mysql (charset #83) in the /var/lib/mysql/HOSTNAME.err file.
You can fix this issue by appending the below line in file “/usr/share/mysql/charsets/Index”
cp1251 83
Restart the mysql service after this modification.
