Can you *read* leveldb data without the proper comparator?
you may fake it by passing exactly the same comparator name to a custom comparator in plyvel. that comparator may work differently from the one originally used to create the database. that would get you past the first hurdle i guess.
but since leveldb does not provide a read-only mode of operation, there may be a background thread kicking in to do some compaction while you read the database. and since the comparator is mishaving, this can lead to data loss and destruction of your database.