message: Only use RLU for FlatDb (lmdb is memmap-ed)
diff: @@ -67,11 +67,11 @@ import TransactionDb from './engines/TransactionDb';
  export default class DiskDb extends TransactionDb {
  constructor (base: string, name: string, options?: BaseDbOptions) {
  super(
  - new LruDb(
  options && options.isNative
  - ? new FileFlatDb(base, name, options)
  - : new LmDb(base, name, options)
  + ? new LruDb(
  + new FileFlatDb(base, name, options)
  )
  + : new LmDb(base, name, options)
  );
  }
  }
  