select
  FILE_MAP_IDX,                            -- FILE_MAP_IDX NUMBER
  EXT_NUM,                                 -- EXT_NUM NUMBER
  EXT_ELEM_OFF,                            -- EXT_ELEM_OFF NUMBER
  EXT_SIZE,                                -- EXT_SIZE NUMBER
  EXT_FILE_OFF,                            -- EXT_FILE_OFF NUMBER
  EXT_TYPE,                                -- EXT_TYPE VARCHAR2(6)
  ELEM_IDX                                 -- ELEM_IDX NUMBER
from
  gv$map_file_extent
where
  inst_id = USERENV('Instance')