Journaling typically implies that there is a separate log of operations/changes, but the main data file (the BTree) is still updated in-place. You can then use the journal to roll back the changes if necessary.
RethinkDB's storage engine doesn't have a journal -- the main data file is essentially journaled, which is quite different from the traditional meaning of the word.
RethinkDB's storage engine doesn't have a journal -- the main data file is essentially journaled, which is quite different from the traditional meaning of the word.