select ( select sum(bytes)/1024/1024/1024 data_size from dba_data_files ) + ( select nvl(sum(bytes),0)/1024/1024/1024 temp_size from dba_temp_files ) + ( select sum(bytes)/1024/1024/1024 redo_size from sys.v_$log ) + ( select sum(BLOCK_SIZE*FILE_SIZE_BLKS)/1024/1024/1024 controlfile_size from v$controlfile) “Size in GB” from dual;