"bzr commit" takes 17 minutes?

[Paul Eggert]

When I do even trivial bzr commits to the Emacs trunk
it takes an amazingly long time:

> $ time bzr commit -m 'Elaborate my most-recent ChangeLog entry.'
> Committing to: bzr+ssh://address@hidden/emacs/trunk/
> modified ChangeLog
  [here is where the long delay occurs]
> Committed revision 103419.
> 
> real    17m33.115s
> user    0m0.390s
> sys     0m0.170s

Are other committers observing such bad performance?
What could explain the performance problem?

I'm pretty well connected to the Internet,
and have a reasonably fast machine, so I don't
think it's my processor or network connection.
I don't see a similar problem with git commits
to Savannah, for example.