标签归档：段头坏块

segment header异常对象删除处理

发表于 2022 年 4 月 14 日 由 惜分飞

对于某些极端情况下，segment header出现损坏的对象该如何处理,这里通过一个实验来说明这类情况该如何处理,创建表并查询相关segment信息

SQL> create tablespace t_xff datafile '/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf' size 128M autoextend on;

Tablespace created.

SQL> create table t_xifenfei tablespace t_xff as select * from dba_objects;

Table created.

SQL> select header_file,header_block from dba_SEGMENTS where segment_name='T_XIFENFEI'  and owner='SYS';

HEADER_FILE HEADER_BLOCK
----------- ------------
          5          130
----segment header 为 file 5，block 130

SQL> select   EXTENT_ID , FILE_ID ,BLOCK_ID  from dba_extents where segment_name='T_XIFENFEI'  and owner='SYS';

 EXTENT_ID    FILE_ID   BLOCK_ID
---------- ---------- ----------
         0          5        128
         1          5        136
         2          5        144
         3          5        152
         4          5        160
         5          5        168
         6          5        176
         7          5        184
         8          5        192
         9          5        200
        10          5        208
        11          5        216
        12          5        224
        13          5        232
        14          5        240
        15          5        248
        16          5        256
        17          5        384
        18          5        512
        19          5        640
        20          5        768
        21          5        896
        22          5       1024
        23          5       1152
        24          5       1280

25 rows selected.

---有25个extent信息

SQL> select * from dba_free_space where file_id=5;

TABLESPACE_NAME                   FILE_ID   BLOCK_ID      BYTES     BLOCKS
------------------------------ ---------- ---------- ---------- ----------
RELATIVE_FNO
------------
T_XFF                                   5       1408  122683392      14976
           5
--空闲block是从1408开始

模拟segment header损坏(通过dd破坏block)

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> 
SQL> 
SQL> 
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@xifenfei ~]$ 
[oracle@xifenfei ~]$ 
[oracle@xifenfei ~]$echo xifenfei.com|dd of=/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf bs=8192 conv=notrunc seek=130
0+1 records in
0+1 records out
17 bytes (17 B) copied, 5.4389e-05 s, 313 kB/s
[oracle@xifenfei ~]$ dbv file=/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf

DBVERIFY: Release 11.2.0.4.0 - Production on Wed Apr 13 20:29:41 2022

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /u01/app/oracle/oradata/orcl/t_xifenfei01.dbf
Page 130 is marked corrupt
Corrupt block relative dba: 0x01400082 (file 5, block 130)
Bad header found during dbv: 
Data in bad block:
 type: 119 format: 7 rdba: 0x65666978
 last change scn: 0x632e.6965666e seq: 0x6f flg: 0x6d
 spare1: 0x77 spare2: 0x2e spare3: 0x0
 consistency value in tail: 0xada72301
 check value in block header: 0xf30a
 computed block checksum: 0x5eb9



DBVERIFY - Verification complete

Total Pages Examined         : 16384
Total Pages Processed (Data) : 1234
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 0
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 154
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 14995
Total Pages Marked Corrupt   : 1
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 6466979 (0.6466979)

查询表数据报错

[oracle@xifenfei ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Wed Apr 13 20:29:48 2022

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area  734892032 bytes
Fixed Size                  2256872 bytes
Variable Size             452984856 bytes
Database Buffers          276824064 bytes
Redo Buffers                2826240 bytes
Database mounted.
Database opened.
SQL> select count(1) from t_xifenfei;
select count(1) from t_xifenfei
                     *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 5, block # 130)
ORA-01110: data file 5: '/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf'

查询extent信息为空

SQL> select   EXTENT_ID   , FILE_ID   ,BLOCK_ID  from dba_extents where segment_name='T_XIFENFEI'  and owner='SYS';

no rows selected

SQL> select header_file,header_block from dba_SEGMENTS where segment_name='T_XIFENFEI'  and owner='SYS';

HEADER_FILE HEADER_BLOCK
----------- ------------
          5          130

SQL> select * from dba_free_space where file_id=5;

TABLESPACE_NAME                   FILE_ID   BLOCK_ID      BYTES     BLOCKS
------------------------------ ---------- ---------- ---------- ----------
RELATIVE_FNO
------------
T_XFF                                   5       1408  122683392      14976
           5

尝试删除表报错

SQL> drop table t_xifenfei;
drop table t_xifenfei
           *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 5, block # 130)
ORA-01110: data file 5: '/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf'

通过加purge删除成功

SQL> drop table t_xifenfei purge;

Table dropped.

删除表成功，但是磁盘空间未释放，通过查询确认变为一个临时段

SQL> select * from dba_free_space where file_id=5;

TABLESPACE_NAME                   FILE_ID   BLOCK_ID      BYTES     BLOCKS
------------------------------ ---------- ---------- ---------- ----------
RELATIVE_FNO
------------
T_XFF                                   5       1408  122683392      14976
           5


SQL> select segment_name,segment_type,owner from dba_segments where header_file=5;

SEGMENT_NAME
--------------------------------------------------------------------------------
SEGMENT_TYPE       OWNER
------------------ ------------------------------
5.130
TEMPORARY          SYS

清理临时段,彻底删除segment header异常对象删除后遗症

SQL> exec dbms_space_admin.segment_corrupt('T_XFF',5,130); 

PL/SQL procedure successfully completed.

SQL> exec dbms_space_admin.segment_drop_corrupt('T_XFF',5,130);

PL/SQL procedure successfully completed.

SQL> exec DBMS_SPACE_ADMIN.TABLESPACE_REBUILD_BITMAPS ('T_XFF');

PL/SQL procedure successfully completed.

SQL> select segment_name,segment_type,owner from dba_segments where header_file=5;

no rows selected

SQL> select * from dba_free_space where file_id=5;

TABLESPACE_NAME                   FILE_ID   BLOCK_ID      BYTES     BLOCKS
------------------------------ ---------- ---------- ---------- ----------
RELATIVE_FNO
------------
T_XFF                                   5        128  133169152      16256
           5
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