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[펌] alter table ... allocate extent 문 - DBA_EXTENTS

From : http://radiocom.kunsan.ac.kr/lecture/oracle/dictionary/dba_extents.html

dba_extents

---

extents에 관한 정보를 담고 있다.

SQL> select owner, segment_name, bytes, blocks
  2> from dba_extents;

OWNER                SEGMENT_NAME   EXTENT_ID      BYTES     BLOCKS
-------------------- ------------- ---------- ---------- ----------
SYS                  _SYSSMU9$     1               65536          8
SYS                  _SYSSMU10$    0               65536          8
SYS                  _SYSSMU10$    1               65536          8
 
6492 rows selected.
 
SQL> 
SQL> select tablespace_name, count(*) segments, sum(bytes) bytes
  2  from dba_segments
  3  group by tablespace_name;
 
TABLESPACE_NAME                  SEGMENTS      BYTES
------------------------------ ---------- ----------
SYSAUX                               3178  319094784
SYSTEM                               1147  462028800
UNDOTBS1                               10    4587520
USERS                                   9     589824
 
SQL> 

alter table 문에 의한 extent할당과 해제