Changing apache user

[Compact]

When I change the apache user, should I have to change anything else like permissions? When I change it the php is not able to connect to the mysql server.

[capitalfellow]

maybe. If the webserver starts up and you can connect browse pages & PHP scripts then perhaps no. If the webserver isn't running at all then perhaps yes.

try 'ps -ef|grep httpd' to see if its running.

If it is running look at the PHP script that the webserver is executing and test if the user that PHP script is using can connect to MySQL via command line.