had performed an upgrade from 6.5 to 6.15 yesterday.

1) how do i go about changing the database collation? do i need to export the db and recreate it? if so, please let me know how to
2) also, where is the config file that defines the db connection values. like server IP, userid, password
3) do not know where to update the MaxTotal as i can't find it in the server.xml
thanks!