Limit size of the 'recycle bin' of deleted libraries
I was wondering why Memento was using so much of my phone's internal storage & why it's backups were getting so big... I only just discovered it was because my "deleted" libraries were not actually deleted! I had 9 large libraries in Memento's hidden 'recycle bin'.
It was quite laborious to manually delete each one (a "delete all" option would be great), but once I did Memento's internal storage usage & backup size dropped by 37%. I think Memento is also noticeably faster as a result.
So please limit the size of Memento's hidden 'recycle bin'. Since databases can be very small or very large, I don't think a "max size in MB" will work very well. Instead I suggest putting a limit on the number and/or age of the deleted libraries. Thus libraries older than say 2 weeks would be deleted, until there were no more than say 3 libraries left. This would ensure that if I deleted say 5 libraries, I could recover all 5 (unless I waited longer than 2 weeks).
Of course the maximum number & age of libraries on the recycle bin would need to be configurable.