A recent mysql update from portage requires this to get it back up and running:

mysql_upgrade -p
/etc/init.d/mysql restart

There’s all kinds of noise out there about this breakage, but this bug has the most accurate information. Fix:

emerge -1 redland; emerge -1 soprano; emerge -1 kdelibs

Carry on… sigh…

The article is on the wiki, check it out if you have a minute and see what you think.