V$FILESPACE_USAGE summarizes space allocation information of each datafile and tempfile.

Column Datatype Description
TABLESPACE_ID NUMBER ID of the tablespace to which the file belongs
RFNO NUMBER Relative file number of the file
ALLOCATED_SPACE NUMBER Total allocated space in the file
FILE_SIZE NUMBER Current file size
FILE_MAXSIZE NUMBER Maximum file size
CHANGESCN_BASE NUMBER SCN base of the last change to the file
CHANGESCN_WRAP NUMBER SCN wrap of the last change to the file
FLAG NUMBER Flags for file attributes