logging stuff

(Responding to the deafening silence regarding my posts a couple of days
ago about logging dbnames and disconnections) ;-)

The dbname patch is now done. If nobody objects to the format
("[db:yourdbname]") I'll submit it - I did it that way to make it fairly
easy to split a log file based on it, although you would have to be
careful with multiline log entries such as query strings. It is
intentionally minimalist.

I had some thoughts about logging disconnections - I can see a way to do
it via an on_proc_exit handler, I think. Then I started wondering if it
might be useful to log session times instead of just noting a disconnect
and letting the user have to calculate the time.

But I won't bother with this if there's no interest. *I* have no current
use for it, but I could well imagine others might. (I might too in the
future if I wanted to debug my connection pooling app).

cheers

andrew