Comment 8 for bug 1642068

If you install/remove on a loop, this will create changes which are kept in memory until they are pruned. This happens in the period of three days for successful ones, and a week for unsuccessful ones (which are aborted, and later pruned). Eventually we'll need to move to a model where this data is kept on disk with proper transactional control around it, but for now this is a cheap way for us to get going.