在一些特殊的情况下(比如ORA-00600 [15267],ORA-00600 [KKDLCOB-OBJN-EXISTS],Ora-600 [15260])，考虑需要把dba_objects中的object_id往前推进，这里通过试验的方法实现该功能
数据库版本信息

SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Prod
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production

分析obj和dataobj

SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
     51887         51907

SQL> select name from obj$ where obj#=51887;

NAME
------------------------------
T_DUL

SQL> select name from obj$ where dataobj#=51907;

NAME
------------------------------
_NEXT_OBJECT

SQL> select object_id,data_object_id from dba_objects where object_name='_NEXT_OBJECT';

no rows selected

为什么dba_objects中无_NEXT_OBJECT
因为dba_objects视图中跳过了_NEXT_OBJECT这条记录

测试创建新表后obj和dataobj的变化

SQL>  create table t_xff as select * from dual;

Table created.

SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
     51898         51907

SQL> select name from obj$ where obj#=51898;

NAME
------------------------------
T_XFF

SQL> select max(object_id),max(data_object_id) from dba_objects where object_name='T_XFF';

MAX(OBJECT_ID) MAX(DATA_OBJECT_ID)
-------------- -------------------
         51898               51898

通过测试可以确定,obj发生增加,但是dataobj不一定增加(因为dataobj本身比obj大，如果出现obj>dataobj那属于异常情况）

测试数据库重启obj和dataobj是否会跳号

---正常重启数据库
SQL> SHUTDOWN IMMEDIATE;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> STARTUP
ORACLE instance started.

Total System Global Area  260046848 bytes
Fixed Size                  1266920 bytes
Variable Size              83888920 bytes
Database Buffers          171966464 bytes
Redo Buffers                2924544 bytes
Database mounted.
Database opened.
SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
     51898         51907

---强制重启数据库
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  260046848 bytes
Fixed Size                  1266920 bytes
Variable Size              83888920 bytes
Database Buffers          171966464 bytes
Redo Buffers                2924544 bytes
Database mounted.
Database opened.
SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
     51898         51907

通过这个证明obj和dataobj没有因为数据库重启而发生改变

实现obj跳号

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup restrict
ORACLE instance started.

Total System Global Area  260046848 bytes
Fixed Size                  1266920 bytes
Variable Size              83888920 bytes
Database Buffers          171966464 bytes
Redo Buffers                2924544 bytes
Database mounted.
Database opened.
SQL>  update obj$ set dataobj#=1000000 where name='_NEXT_OBJECT';  

1 row updated.

SQL> commit;

Commit complete.

SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  260046848 bytes
Fixed Size                  1266920 bytes
Variable Size              83888920 bytes
Database Buffers          171966464 bytes
Redo Buffers                2924544 bytes
Database mounted.
Database opened.

SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
     51898       1000000

SQL> create table t_www_xifenfei_com as select * from dual;

Table created.

SQL> select max(obj#),max(dataobj#) from obj$;

 MAX(OBJ#) MAX(DATAOBJ#)
---------- -------------
   1000000       1000010

SQL> select max(object_id),max(data_object_id) from dba_objects;

MAX(OBJECT_ID) MAX(DATA_OBJECT_ID)
-------------- -------------------
       1000000             1000000

SQL> select object_name from dba_objects where object_id=1000000;

OBJECT_NAME
----------------------------------------------------------------
T_WWW_XIFENFEI_COM

通过丢_NEXT_OBJECT的更新实现obj和dataobj跳号(变成100w)

有老朋友找到我,说一个客户的数据库异常,问题是asm无法正常mount,提示是缺少两块磁盘.问我是否可以恢复.因为是内网环境,通过他那边发过来的零零散散的信息,大概分析如下
asm alert日志报错
ERROR: diskgroup DGROUP1 was not mounted

Fri Aug 12 16:03:12 EAT 2016
SQL> alter diskgroup DGROUP1 mount 
Fri Aug 12 16:03:12 EAT 2016
NOTE: cache registered group DGROUP1 number=1 incarn=0xf6781b5c
Fri Aug 12 16:03:12 EAT 2016
NOTE: Hbeat: instance first (grp 1)
Fri Aug 12 16:03:16 EAT 2016
NOTE: start heartbeating (grp 1)
Fri Aug 12 16:03:16 EAT 2016
NOTE: cache dismounting group 1/0xF6781B5C (DGROUP1) 
NOTE: dbwr not being msg'd to dismount
ERROR: diskgroup DGROUP1 was not mounted

前台尝试mount asm 磁盘组报错ORA-15042

从这里可以明显的看出来asm 磁盘组无法正常mount,是由于缺少asm disk 15,16.如果想恢复asm,最好的方法就是找出来这两个磁盘.通过kfed对现在的磁盘进行分析,最后我们发现asm disk 14对应的磁盘为disk160,,asm disk 17对应的disk163,根据第一感觉很可能是disk161和disk161两块盘异常,让机房检查硬件无任何告警

OS层面分析
省略和本次结论无关的记录

ls -l /dev/rdisk
crw-rw----   1 oracle     dba         13 0x000070 Jan  1  2016 disk160
crw-rw----   1 oracle     dba         13 0x000073 Jan  1  2016 disk163

ls -l /dev/disk
brw-r-----   1 bin        sys          1 0x000070 Jan 13  2015 disk160
brw-r-----   1 bin        sys          1 0x000071 Jan 13  2015 disk161
brw-r-----   1 bin        sys          1 0x000072 Jan 13  2015 disk162
brw-r-----   1 bin        sys          1 0x000073 Jan 13  2015 disk163

这里我们发现在hp unix中/dev/disk下面磁盘都存在,但是/dev/rdisk下面丢失，通过ioscan相关命令继续分析

ioscan -fNnkC disk
disk    160  64000/0xfa00/0x70  esdisk   CLAIMED     DEVICE       HP      OPEN-V
                      /dev/disk/disk160   /dev/rdisk/disk160
disk    161  64000/0xfa00/0x71  esdisk   CLAIMED     DEVICE       HP      OPEN-V
                      /dev/disk/disk161
disk    162  64000/0xfa00/0x72  esdisk   CLAIMED     DEVICE       HP      OPEN-V
                      /dev/disk/disk162
disk    163  64000/0xfa00/0x73  esdisk   CLAIMED     DEVICE       HP      OPEN-V
                      /dev/disk/disk163   /dev/rdisk/disk163

这里我们基本上可以确定是/dev/rdisk下面的盘发生丢失.进一步分析,因为rdisk是聚合后的盘符,那我们分析聚合前的盘符是否正常

ioscan -m dsf
/dev/rdisk/disk160       /dev/rdsk/c29t12d4
                         /dev/rdsk/c28t12d4
/dev/rdisk/disk163       /dev/rdsk/c29t12d7
                         /dev/rdsk/c28t12d7

ls -l /dev/rdsk
crw-r-----   1 bin        sys        188 0x1dc000 Apr 22  2014 c29t12d0
crw-r-----   1 bin        sys        188 0x1dc100 Apr 22  2014 c29t12d1
crw-r-----   1 bin        sys        188 0x1dc300 Jan 13  2015 c29t12d3
crw-r-----   1 bin        sys        188 0x1dc400 Jan 13  2015 c29t12d4
crw-r-----   1 bin        sys        188 0x1dc500 Jan 13  2015 c29t12d5
crw-r-----   1 bin        sys        188 0x1dc600 Jan 13  2015 c29t12d6
crw-r-----   1 bin        sys        188 0x1dc700 Jan 13  2015 c29t12d7

crw-r-----   1 bin        sys        188 0x1cc100 Apr 22  2014 c28t12d1
crw-r-----   1 bin        sys        188 0x1cc300 Jan 13  2015 c28t12d3
crw-r-----   1 bin        sys        188 0x1cc400 Jan 13  2015 c28t12d4
crw-r-----   1 bin        sys        188 0x1cc500 Jan 13  2015 c28t12d5
crw-r-----   1 bin        sys        188 0x1cc600 Jan 13  2015 c28t12d6
crw-r-----   1 bin        sys        188 0x1cc700 Jan 13  2015 c28t12d7

通过这里我们基本上可以大概判断出来/dev/rdsk/c28t12d5,/dev/rdsk/c28t12d6,/dev/rdsk/c29t12d5,/dev/rdsk/c29t12d6就是我们需要找的/dev/rdisk/disk161和disk162的聚合之前的盘符.也就是说,现在我们判断只有/dev/rdisk下面的字符设备有问题,其他均正常.

通过系统命令修复异常

insf -e -H 64000/0xfa00/0x71
insf -e -H 64000/0xfa00/0x72

现在已经可以正常看到/dev/rdisk/disk161和/dev/rdisk/disk162盘符,初步判断,os层面盘符已经恢复正常.修改磁盘权限和所属组

chmod 660 /dev/rdisk/disk161
chmod 660 /dev/rdisk/disk162
chown oracle:dba /dev/rdisk/disk161
chown oracle:dba /dev/rdisk/disk162

正常启动asm,mount磁盘组,open数据库

这次的恢复,主要是从操作系统层面判断解决问题,从而实现数据库完美恢复,数据0丢失.有类似恢复案例:分区无法识别导致asm diskgroup无法mount