Reports the row-group byte target -- the EFFECTIVE value, so a program that never set it is
told 268435456 rather than the 0 that is stored.
integer(int64) function parquet_get_target_row_group_bytes() result(n) n = cfg_target_row_group_bytes if (n <= 0) n = target_row_group_bytes_builtin end function parquet_get_target_row_group_bytes