Hello
I tested Peter's patch and it works well.
I don't see any performance problem on my notebook
last discussion
http://archives.postgresql.org/message-id/CAK3UJRHXgnChP9J5RuOEMEtFB0E9awPhNOV=RQuPwK6VX-ZaPA@mail.gmail.com
so we can do more - we can join this completation with "," too - but
it can add false compleations inside FROM clause.
Probably we are near of end of enhancing completation - for doing
usable completation we need syntax analysing :(
Regards
Pavel Stehule