Pro tip: Exclude /var/lib/docker from mlocate db

If you use docker much at all, I highly recommend excluding it from mlocate, if you use it. At least, with the btrfs version of docker (the only one worth using), you end up with what looks, to the filesystem, like an immense tree hanging off /var/lib/docker. And naive mlocate iterates through the entire lot, indexing it.