Closing database connection when die() in script

Imported From: http://groups.google.com/group/in-portal-dev/browse_thread/thread/22da5ee2d56401c5#

One recent project has shown, that having die() executed frequently in
code might cause database connection to "freeze", in other words -
this "dead" connection does not disconnect and as a result, maximum
allowed db connections becomes a cause for other sites, running on
same server, to receive "cannot connect to database server - maximum
allowed connections exceeded".
I propose handling database closure process within __destruct() method
inside of kDbConnection class, as this method should be executed even
if die() is called.