Shouldn't portage offer some means to recover from a corrupted vdb?

I just stumbled upon
<http://forums.gentoo.org/viewtopic-t-900382-start-0-postdays-0-postorder-asc-highlight-.html>
and it seems really bad.

It would suck if the only solution to this is reinstall (I remember
package database becoming corrupted in some RPM-based distro I had years
ago and I hated it).

If the recovery is already possible, we should get a doc explaining what
to do. Otherwise it'd be really great to implement some recovery logic.

I think we can't salvage much from a corrupted db (anything can happen,
and the reporter mentions some code being present in the files), but at
least "emerge -e world" or equivalent should be possible.