测试环境磁盘空间不足，所以drop一些无用的大表，但是发现空间没有变化，df -h还是没有释放出磁盘空间来。
SQL> set line 200
SQL> set pagesize 200
SQL> col name format A150
SQL> SELECTUPPER(F.TABLESPACE_NAME) "表空间名",
2 D.TOT_GROOTTE_MB "表空间大小(M)",
3 D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)",
4 TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) /D.TOT_GROOTTE_MB * 100,2),'990.99') || '%' "使用比",
5 F.TOTAL_BYTES "空闲空间(M)",
6 F.MAX_BYTES "最大块(M)"
7 FROM (SELECT TABLESPACE_NAME,
8 ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES,
9 ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES
10 FROM SYS.DBA_FREE_SPACE
11 GROUP BY TABLESPACE_NAME) F,
12 (SELECT DD.TABLESPACE_NAME,
13 ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB
14 FROM SYS.DBA_DATA_FILES DD
15 GROUP BY DD.TABLESPACE_NAME) D
16 WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
17 ORDER BY 1;
表空间名 表空间大小(M) 已使用空间(M) 使用比 空闲空间(M) 最大块(M)
------------------------------------------- ------------- -------- ----------- ----------
HELP 500 5.19 1.04% 494.81 494.81
ORCTSTU 32406.63 15545.69 47.97% 16860.94 72
SYSAUX 900 689.94 76.66% 210.06 204.94
SYSTEM 1110 1005.31 90.57% 104.69 95.44
UAAP 500 143.37 28.67% 356.63 290.38
UNDOTBS1 6485 331.25 5.11% 6153.75 3534
USERS 461.25 394.44 85.52% 66.81 22.19
10 rows selected
SQL>
看到ORCTSTU表空间只使用了49%，使用了15G空间，而ORCTSTU表空间占据的总磁盘空间为32G，所以我们可以收缩ORCTSTU到16G左右，这样就释放出了将近16G的空间了。
去查看下此表空间所在的数据文件，如下所示：
SQL> SELECT file_id,file_name FROM DBA_DATA_FILES D WHERED.TABLESPACE_NAME = 'ORCTSTU';
FILE_ID FILE_NAME
------------------------------------------------------------------------------------------
5D:\ORACLE\ORASERVER\ORADATA\ORCTSTUEX\POWERDES\ORCTSTU01.DBF
SQL>
准备收缩到18G，执行如下报错
SQL> alter database datafile'/home/oradata/powerdes/orctstu01.dbf' resize 1800M;
alter database datafile'/home/oradata/powerdes/orctstu01.dbf' resize 1800M
*
ERROR at line 1:
ORA-03297: file contains used data beyondrequested RESIZE value
SQL>
select file_id,max(block_id+blocks-1)HWM,block_id
from dba_extents
where file_id=5
group by file_id,block_id;
可以看到基本没有任何改变，但是根据我的直观感觉，确实没有多少表了，空间也确实都腾出来了。可以简单的验证一下,数据文件是5号，使用dba_extents可以看到占用的空间情况和对应的块的情况。
select file_id,max(block_id+blocks-1)HWM,block_id
from dba_extents
where file_id=5
group by file_id,block_id;
6519 5 4194047 4193920
3469 5 4187263 4186368
8137 5 4186367 4186240
3919 5 4186239 4186112
3033 5 4186111 4185984
9526 5 4185983 4185856
9113 5 4185855 4184832
9669 5 4184775 4184768
1166 5 4184767 4184760
2304 5 4184743 4184736
7215 5 4184735 4184728
4933 5 4184727 4184720
......
通过对比HWM和block_id的值，看到有很多都是空间占用差别比较大的。
我们来在这个基础上做一个简单的分析。首先得到5号数据文件中，块号最大的数据块block_id。
SQL> SELECT MAX(block_id) FROMdba_extents WHERE tablespace_name = 'ORCTSTU';
MAX(BLOCK_ID)
-------------
4193920
SQL>
值为： 4193920
再查看下一个block的容量大小
SQL> show parameter db_block_size;
NAME TYPE VALUE
----------------------------------------------- ------------------------------
db_block_size integer 8192
SQL>
SELECT 4193920*8192/1024/1024 FROM dual;
SQL> SELECT 4193920*8192/1024/1024/1024FROM dual;
4193920*8192/1024/1024/1024
---------------------------
31.9970703
SQL>
计算出来大概是32G左右，再去磁盘看实际的数据文件大小
[oracle@edustu4 ~]$ ll -h/home/oradata/powerdes/orctstu01.dbf
-rw-r-----. 1 oracle oinstall 32G May 1618:06 /home/oradata/powerdes/orctstu01.dbf
[oracle@edustu4 ~]$
也是32G左右，和实际的磁盘的数据文件的大小一致，
看看这个最大4193920的数据块所在的extent对应的segment信息是否是已经被drop到的table。
select segment_name,owner from dba_extentswhere block_id=3507584;
SQL> select segment_name,owner fromdba_extents where block_id=1942656;
SEGMENT_NAME
--------------------------------------------------------------------------------
OWNER
------------------------------
RES_APPROVE_SHARE
ORCTSTU
SQL>
这个表不是一件被drop的哪些表记录，表RES_APPROVE_SHARE正在被应用程序使用着，也就说明了报错，所以resize的时候报错ORA-03297: file contains used data beyond requested RESIZE value，block不能释放掉，因为正在被使用。
这个时候通过正常的resize已经不能解决问题了，怎么办？可以采用expdp、impdp的方式重新生成新的表空间和数据文件，然后删除旧的表空间和数据文件。
create tablespace ORCTSTU_2
logging
datafile '/home/oradata/powerdes/orctstu02.dbf'
size 50m
autoextend on
next 50m ;
alter table RES_APPROVE_SHARE move ORCTSTU_2;
ORA-14133: ALTER TABLE MOVE cannot becombined with other operations
alter table orctstu.RES_APPROVE_SHARE movetablespace ORCTSTU_2;
先建立管道目录
CREATEOR REPLACE DIRECTORY dir_dump_t1 AS'/home/oracle/expdpimpdp';
开始导出export
[oracle@edustu4 ~]$ expdp orctstu/testpd2015@PD1 directory=dir_dump_t1schemas=orctstu dumpfile=TEST2_PD_20150518.dmp
Export:Release 11.2.0.1.0 - Production on Mon May 18 17:06:42 2015
Copyright(c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Connectedto: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bitProduction
Withthe Partitioning, OLAP, Data Mining and Real Application Testing options
Starting"ORCTSTU"."SYS_EXPORT_SCHEMA_02": orctstu/********@PD1 directory=dir_dump_t1schemas=orctstu dumpfile=TEST2_PD_20150518.dmp
Estimatein progress using BLOCKS method...
Processingobject type SCHEMA_EXPORT/TABLE/TABLE_DATA
Totalestimation using BLOCKS method: 7.483 GB
Processingobject type SCHEMA_EXPORT/USER
Processingobject type SCHEMA_EXPORT/SYSTEM_GRANT
.....................................................
Processingobject type SCHEMA_EXPORT/POST_SCHEMA/PROCOBJ
.. exported "ORCTSTU"."RES_APPROVE_CONTENT" 44.01 MB 350923 rows
.. exported "ORCTSTU"."RECEIPT_BILL" 569.3 MB 2064823 rows
.....................................................
.. exported "ORCTSTU"."ZS_PLAN_LEAVE_MESSAGE" 0 KB 0 rows
.. exported "ORCTSTU"."ZS_PLAN_MESSAGE" 0 KB 0 rows
Mastertable "ORCTSTU"."SYS_EXPORT_SCHEMA_02" successfullyloaded/unloaded
******************************************************************************
Dumpfile set for ORCTSTU.SYS_EXPORT_SCHEMA_02 is:
/home/oracle/expdpimpdp/TEST2_PD_20150518.dmp
Job"ORCTSTU"."SYS_EXPORT_SCHEMA_02" successfully completed at17:11:13
[oracle@edustu4~]$
删除用户
drop user orctstu cascade;
删除表空间
drop tablespace orctstu including contents anddatafiles;
然后重启oracle
shutdown immediate
startup
查看磁盘空间，已经释放出来了
[oracle@edustu4 expdpimpdp]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 57G 21G 34G 38% /
tmpfs 12G 2.1G 10G 18% /dev/shm
/dev/sda1 194M 32M 153M 18% /boot
/dev/mapper/vg001-lv001
63G 12G 49G 20% /home/oradata
df:`/root/.gvfs': Permission denied
[oracle@edustu4expdpimpdp]$
重新创建用户
createtablespace ORCTSTU
logging
datafile'/home/oradata/powerdes/orctstu01.dbf'
size50m
autoextendon
next50m
extentmanagement local;
CREATEUSER orctstu PROFILE "DEFAULT" IDENTIFIED BY "testpd2015" DEFAULT TABLESPACE ORCTSTU ACCOUNTUNLOCK;
GRANTconnect,resource TO orctstu;
grantdba to orctstu;
SQL>create tablespace ORCTSTU
logging
datafile'/home/oradata/powerdes/orctstu01.dbf'
size50m
autoextendon
next50m
extentmanagement local; 2 3 4 5 6 7
Tablespacecreated.
SQL>
SQL>CREATE USER orctstu PROFILE "DEFAULT" IDENTIFIED BY "testpd2015"DEFAULT TABLESPACE ORCTSTU ACCOUNT UNLOCK;
Usercreated.
SQL>GRANT connect,resource TO orctstu;
Grantsucceeded.
SQL>grant dba to orctstu;
Grantsucceeded.
SQL>
导入命令：
impdporctstu/testpd2015@PD1 directory=dir_dump_t1 dumpfile=TEST2_PD_20150518.dmpnologfile=y
导入过程如下：
......
Processingobject type SCHEMA_EXPORT/EVENT/TRIGGER
ORA-39082:Object type TRIGGER:"ORCTSTU"."LOGON_DENIED_TO_ALERT"created with compilation warnings
ORA-39082:Object type TRIGGER:"ORCTSTU"."LOGON_DENIED_TO_ALERT"created with compilation warnings
Processingobject type SCHEMA_EXPORT/TABLE/INDEX/FUNCTIONAL_AND_BITMAP/INDEX
Processingobject typeSCHEMA_EXPORT/TABLE/INDEX/STATISTICS/FUNCTIONAL_AND_BITMAP/INDEX_STATISTICS
Processingobject type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processingobject type SCHEMA_EXPORT/JOB
Processingobject type SCHEMA_EXPORT/POST_SCHEMA/PROCOBJ
Job"ORCTSTU"."SYS_IMPORT_FULL_01" completed with 45 error(s)at 20:36:08
[oracle@edustu4admin]$
PS:impdp导入的时候，是从最大的表开始导入的，先导入数据，最后重建索引，导入各种其它objects。
SQL> drop user orctstu cascade;
drop user orctstu cascade
*
ERROR at line 1:
ORA-04098: trigger 'ORCTSTU.LOGON_DENIED_TO_ALERT'is invalid and failed
re-validation
ORA-01940: cannot drop a user that iscurrently connected
SQL>
解决办法：直接lsnrctl stop;然后重新执行drop user操作
参考文章地址： http://mp.weixin.qq.com/s?__biz=MjM5ODEzNDA4OA==&mid=210054237&idx=1&sn=a8a10b9275233876cc218616c7075422&scene=1&key=c468684b929d2be2b0ffb1ce3cccad13f8704c151f3b15e9fea067c200d7b5bb313c06d9c65bf99921aa10386672b9ea&ascene=1&uin=MTAwMDg2MTU4Mw%3D%3D&devicetype=webwx&version=70000001&pass_ticket=%2BXWq8edLrEPcVZeIuoKStojLYf546G8W1JvUNaVQXBTp02zaoqaiSoTTOdqwc3IG