Oracle -在线回缩表

conn scott/tiger
DROP TABLE EMP1 PURGE;
CREATE TABLE EMP1 AS SELECT * FROM EMP;

alter table emp1 enable row movement; 
-- 启动回缩特性     
insert into emp1 select * from emp1; 
/
/

commit;
-- 增加到14000行

-- 分析表的结构     
analyze table emp1 compute statistics; 
select NUM_ROWS,BLOCKS,EMPTY_BLOCKS,AVG_SPACE from tabs where table_name='EMP1'; 
-- 查询高水位    
     
delete emp1 where deptno=30;
commit; 
-- 删除一半的数据     
analyze table emp1 compute statistics; 
-- 分析表的结构     
select NUM_ROWS,BLOCKS,EMPTY_BLOCKS,AVG_SPACE from tabs where table_name='EMP1'; 
-- 查询高水位     
SELECT DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) BLOCK#,COUNT(*) FROM EMP1