Msg#: 4542889 posted 5:41 pm on Feb 11, 2013 (gmt 0)
Opening a connection is an expensive operation. You should only close the connection when you are sure it won't be used again.
However, open connections are automatically destroyed at the end of script resolution. So, although calling mysqli_close() will free up those memory resources for the rest of the script, it's not actually a requirement to call that function at all.