Unlike journal::fixed, journal::variable does not assume that you are working over a contiguous global log (just one per section). The rationale for this was that you need to store consensus messages in multiple views and you want to prune them independently (if you added to a contiguous log, you'd have to track the lowest view active at some index):

We should make a wrapper around journal::variable that provides this contiguous functionality (likely from logic that already exists in adb). This would make implementing much of the adb-related logic MUCH simpler (as there is a ton of logic mapping index to location).