hello sir .
Yesterday , my 7 websites are normal ,but today my 7 websites are totally down and show messages as Error establishing a database connection.

1. i tried to check the wp-config.php in my 7 websites .the results are totally correct.
2. but i go to phpAdmin login to website database.the result is that i cannot login all of my websites .
3. the phpadmin show the messages is that :

2002 - No such file or directory — The server is not responding (or the local server's socket is not correctly configured).

mysqli_real_connect(): (HY000/2002): No such file or directory
Connection for controluser as defined in your configuration failed.

mysqli_real_connect(): (HY000/2002): No such file or directory

hope you can help me to fix it . thanks a million !
from simon chow