anchor.diff:          Reason ->
               {error, Reason}
       end.
  +
  +
  +-spec get_cache_size() ->
  +    {ok, non_neg_integer(), non_neg_integer(), non_neg_integer()} | {error, error()}.
   
   get_cache_size() ->
       Cmd = <<?SYSP_CACHESIZE_GET:32/signed-native>>,
  
positive.code:         Error       -> throw(Error)
      end.
  
  update(Db, Key, Fun) ->
      update(Db, Key, Fun, undefined).
  
  update(Db, Key, Fun, Args) ->
      F = fun() ->
  
negative.code:         Error -> {error, {txn_begin, Error}}
      end.
  
  
  -spec txn_commit() -> ok | error().
  
  txn_commit() ->
      txn_commit([]).
  
  
  -spec txn_commit(Opts :: db_flags()) -> ok | error().
  
  txn_commit(Opts) ->
      Flags = process_flags(Opts),
  