Eliminate warnings from LevelDB API with "g++ -Wall", debug a problem applying write batches to unknown column families.
After multiple open / close cycles, log archive may have remove the log file containing the metadata checkpoint LSN.  That's fine: just scan the whole log in the main recovery loop in that case.
Fix a bad cast, switch from reinterpret_cast to static_cast in an attempt to avoid this kind of thing in the future.