securityd memory hogging

Mac running slow, Keychain keeps telling me Google Desktop has changed and asks for authentication. Do I have a virus, or is something wrong with keychain?

Activity Monitor tells me that securityd is using 1.5GB of memory; something is wrong.

Googling suggests that /var/db/CodeEquivalenceDatabase may be corrupted. Furthermore, it seems that it can rebuild itself, so the lizard's tail treatment is suggested: remove the offending part.

I did the following:

cd /var/db
sudo rm -rf CodeEquivalenceDatabase

sudo rm -rf is serious magic, and can get you in serious trouble; be careful (long ago, I once did cd /dev ; rm -rf mouse * — where I meant mouse* — don't try this at home) ... the faint-of-heart could take a copy of the file instead and remove it later:
mv CodeEquivalenceDatabase CodeEquivalenceDatabase.old

In any case, this seemed to work. After a restart keychain asks me to authenticate access for various apps: SystemUIServer, GoogleDesktopAgent, Mail, ... I do this. Everything seems normal, and securityd is using "only" 28MB of memory (back in the old days, we used to run serious theorem provers in less).