IT博客汇 | 通过update _NEXT_OBJECT 实现obj$.obj#和obj$.dataobj#跳号

通过update _NEXT_OBJECT 实现obj$.obj#和obj$.dataobj#跳号

惜分飞发表于 2016-09-06 03:04:48

标题：通过update _NEXT_OBJECT 实现obj$.obj#和obj$.dataobj#跳号

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)