Today I have noticed after convert tablespace from OFA to OATM, following segment_type appears in the APPLSYSD tablespace. After doing the research, it’s there for long time already.
SQL> col owner for a10
SQL> col segment_name for a10
SQL> col segment_type for a20
SQL> select owner,segment_name, segment_type from dba_segments
2 where tablespace_name=’APPLSYSD’
3 /
OWNER SEGMENT_NA SEGMENT_TYPE
———- ———- ——————–
SYS 8.42 SPACE HEADER
SQL>
Cause
One of the circumstances under which a ‘SPACE HEADER’ segment gets created is if a ‘dictionary managed’ tablespace is migrated to ‘locally managed’ (see dbms_space_admin.tablespace_migrate_to_local()).The space header segment contains the extent bitmap and is allocated during the migration of the tablespace. Since there is no reserved space after the file header (as with locally managed tablespaces) the bitmap segment will be allocated somewhere in the “data” area of the datafile. During its creation the segment will pick up some of the storage attributes (e.g. MAXEXTENTS) from the default storage clause of the tablespace. Once the segment has been created it can neither be dropped nor changed.
Fix
You can ignore these “left-over” objects. Please go ahead and drop old tablespaces.
More information: Notes: 271866.1
