SQL> create tablespace ts_lob datafile '/u01/app/oracle/oradata/DBdb/ts_lob.dbf' size 500m autoextend off;
Tablespace created.
--scott用户创建测试表lob1:
SQL> grant dba to scott;
Grant succeeded.
SQL> conn scott/tiger;
Connected.
SQL> create table lob1(line number,text clob) tablespace ts_lob;
Table created.
SQL> insert into lob1  select line,text from  dba_source;
637502 rows created.
SQL> insert into lob1 select * from lob1;
637502 rows created.
SQL> select count(*) from lob1;
COUNT(*)
----------
1275004
SQL> commit;
Commit complete.
--查询表大小(包含表和lob字段)
select (select nvl(sum(s.bytes/1024/1204), 0)                              -- the table segment size
from dba_segments s
where s.owner = upper('SCOTT')
and (s.segment_name = upper('LOB1'))) +
(select nvl(sum(s.bytes/1024/1024), 0)                              -- the lob segment size
from dba_segments s, dba_lobs l
where s.owner = upper('SCOTT')
and (l.segment_name = s.segment_name and
l.table_name = upper('LOB1') and
l.owner = upper('SCOTT'))) +
(select nvl(sum(s.bytes/1024/1024), 0)                              -- the lob index size
from dba_segments s, dba_indexes i
where s.owner = upper('SCOTT')
and (i.index_name = s.segment_name and
i.table_name = upper('LOB1') and index_type = 'LOB' and
i.owner = upper('SCOTT'))) "total_table_size_M"
FROM DUAL;
total_table_size_M
------------------
239.966154
--查询表大小(不包含lob字段)               
col SEGMENT_NAME for a30
col PARTITION_NAME for a30
SQL> select OWNER,SEGMENT_NAME,PARTITION_NAME,BYTES/1024/1024 M from dba_segments where segment_name='LOB1' and owner='SCOTT';
OWNER                          SEGMENT_NAME                   PARTITION_NAME                          M
------------------------------ ------------------------------ ------------------------------ ----------
SCOTT                          LOB1                                                                 208
--查询表大小(只包含lob字段)       
set lines 200 pages 999
col owner  for a15
col TABLE_NAME for a20
col COLUMN_NAME for a30
col SEGMENT_NAME for a30
select a.owner,
a.table_name,
a.column_name,
b.segment_name,
b.segment_type,
ROUND(b.BYTES / 1024 / 1024)
from dba_lobs a, dba_segments b
where a.segment_name = b.segment_name
and a.owner = 'SCOTT'
and a.table_name = 'LOB1'
union all
select a.owner,
a.table_name,
a.column_name,
b.segment_name,
b.segment_type,
ROUND(b.BYTES / 1024 / 1024)
from dba_lobs a, dba_segments b
where a.index_name = b.segment_name
and a.owner = 'SCOTT'
and a.table_name = 'LOB1';
OWNER           TABLE_NAME           COLUMN_NAME                    SEGMENT_NAME                   SEGMENT_TYPE       ROUND(B.BYTES/1024/1024)
--------------- -------------------- ------------------------------ ------------------------------ ------------------ ------------------------
SCOTT           LOB1                 TEXT                           SYS_LOB0000089969C00002$$      LOBSEGMENT                               63
SCOTT           LOB1                 TEXT                           SYS_IL0000089969C00002$$       LOBINDEX                                  0
--查询ts_lob表空间的表大小排行
SQL> select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments
where tablespace_name='TS_LOB' group by segment_name )
order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  208
SYS_LOB0000089969C00002$$              63
SYS_IL0000089969C00002$$            .0625
--查询lob字段SCOTT_LOB0000089963C00002$$ 、SCOTT_IL0000089963C00002$$:
SQL> col object_name for a30
SQL> select OWNER,OBJECT_NAME,OBJECT_TYPE from dba_objects where OBJECT_NAME in('SYS_LOB0000089969C00002$$','SYS_IL0000089969C00002$$');
OWNER           OBJECT_NAME                    OBJECT_TYPE
--------------- ------------------------------ -------------------
SCOTT           SYS_IL0000089969C00002$$       INDEX
SCOTT           SYS_LOB0000089969C00002$$      LOB
SQL>  select OWNER,TABLE_NAME,COLUMN_NAME,SEGMENT_NAME,TABLESPACE_NAME,INDEX_NAME from dba_lobs where segment_name in('SYS_LOB0000089969C00002$$','SYS_IL0000089969C00002$$');
OWNER           TABLE_NAME           COLUMN_NAME                    SEGMENT_NAME                   TABLESPACE_NAME                INDEX_NAME
--------------- -------------------- ------------------------------ ------------------------------ ------------------------------ ------------------------------
SCOTT           LOB1                 TEXT                           SYS_LOB0000089969C00002$$      TS_LOB                         SYS_IL0000089969C00002$$
SQL>
SQL> select SEGMENT_NAME,bytes /1024/1024 sx from dba_segments where tablespace_name='TS_LOB' and SEGMENT_NAME in('SYS_LOB0000089969C00002$$','SYS_IL0000089969C00002$$');
SEGMENT_NAME                           SX
------------------------------ ----------
SYS_LOB0000089969C00002$$              63
SYS_IL0000089969C00002$$            .0625

SQL>  alter table scott.lob1 drop (text);
Table altered.
SQL> select SEGMENT_NAME,bytes /1024/1024 sx from dba_segments where tablespace_name='TS_LOB' and SEGMENT_NAME in('SYS_LOB0000089969C00002$$','SYS_IL0000089969C00002$$');
no rows selected
SQL> select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  208

--再次添加LOB字段：
SQL> alter  table scott.lob1 add (text clob);
Table altered.
SQL>  select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  208
SYS_LOB0000089969C00002$$           .0625
SYS_IL0000089969C00002$$            .0625

SQL> insert into scott.lob1 select LINE,text from dba_source;
637502 rows created.
SQL> insert into scott.lob1 select LINE,text from dba_source;
637502 rows created.
SQL> commit;
Commit complete.
SQL>  select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  208
SYS_LOB0000089969C00002$$              63
SYS_IL0000089969C00002$$            .0625
--接着试着truncate表LOB1
SQL> truncate table scott.lob1;
Table truncated.
SQL>  select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                .0625
SYS_LOB0000089969C00002$$           .0625
SYS_IL0000089969C00002$$            .0625

SQL> insert into scott.lob1 select LINE,text from dba_source;
637502 rows created.
SQL> insert into scott.lob1 select LINE,text from dba_source;
637502 rows created.
SQL> commit;
Commit complete.
SQL>
SQL>  select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  184
SYS_LOB0000089969C00002$$              63
SYS_IL0000089969C00002$$            .0625

SQL> delete scott.lob1;
1275004 rows deleted.
SQL>
SQL> select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                  184
SYS_LOB0000089969C00002$$              63
SYS_IL0000089969C00002$$              .75
SQL> select count(*) from scott.lob1;
COUNT(*)
----------
0
SQL> truncate table scott.lob1;
Table truncated.
SQL> select * from (select SEGMENT_NAME,sum(bytes)/1024/1024 sx from dba_segments where tablespace_name='TS_LOB' group by segment_name ) order by sx desc;
SEGMENT_NAME                           SX
------------------------------ ----------
LOB1                                .0625
SYS_LOB0000089969C00002$$           .0625
SYS_IL0000089969C00002$$            .0625