GV$MAP_ELEMENT definition in Oracle Database 11.2
GV$MAP_ELEMENT

select
  inst_id,                                 -- INST_ID NUMBER
  elem_name,                               -- ELEM_NAME VARCHAR2(256)
  elem_idx,                                -- ELEM_IDX NUMBER
  elem_cfgid,                              -- ELEM_CFGID VARCHAR2(256)
  decode(                                  -- ELEM_TYPE VARCHAR2(12)
    elem_type,1,'MIRROR',2,'STRIPE',3,'RAID5', 4,'CONCATENATED',5,'PARTITION',6,'DISK',7,'ASMDISK',8,'NONE'),
  to_number(                               -- ELEM_SIZE NUMBER
    decode(elem_size,4294967295,NULL,elem_size)),
  elem_nsubelem,                           -- ELEM_NSUBELEM NUMBER
  elem_descr,                              -- ELEM_DESCR VARCHAR2(256)
  stripe_size,                             -- STRIPE_SIZE NUMBER
  to_number(                               -- LIB_IDX NUMBER
    decode(lib_idx,4294967295,NULL,lib_idx)) 
from
  x$ksfmelem

home |  up