Exclusive lock for database rename

Someone wanted to rename a database while someone else was running a 
rather long pg_dump, so the rename had to wait, and everyone else had 
to wait for the rename because no new connections would be allowed.  
It's clear that we need to prevent new connections to the database 
being renamed, but isn't there a less intrusive way to do that (row 
locks?)?  Right now, everyone with createdb privileges effectively has 
DOS superpowers.

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/