在有些情况下可以通过替换bootstrap$来达到一些目的，如重建object_id小于58的对象。下面是测试常用的2种方式来切换bootstrap$表：1，使用DBMS_DDL_INTERNAL.SWAP_BOOTSTRAP，2，直接修改system数据文件头的信息
1，DBMS_DDL_INTERNAL方法
使用dbms_ddl_internal要求数据库必须启动了upgrade状态，并且版本要求11G以上。
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www.cdhtz.com > startup upgrade; ORACLE instance started.
Total System Global Area 2137886720 bytes Fixed Size 2230072 bytes Variable Size 1493174472 bytes Database Buffers 637534208 bytes Redo Buffers 4947968 bytes Database mounted. Database opened. www.cdhtz.com > create table htz as select * from bootstrap$; Table created. www.cdhtz.com > select * from htz where LINE#=59; LINE# OBJ# ———- ———- SQL_TEXT ——————————————————————————– 59 59 CREATE TABLE BOOTSTRAP$(“LINE#” NUMBER NOT NULL,”OBJ#” NUMBER NOT NULL,”SQL_TEXT ” VARCHAR2(4000) NOT NULL) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 STORAGE ( INITIAL 56K NEXT 1024K MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 OBJN O 59 EXTENTS (FILE 1 BLOCK 520)) 这里删除59这行记录，不然在启动的时候会报重复对象的错误 www.cdhtz.com > delete htz where LINE#=59; 1 row deleted. www.cdhtz.com > commit; Commit complete. www.cdhtz.com > exec DBMS_DDL_INTERNAL.SWAP_BOOTSTRAP(‘HTZ’); PL/SQL procedure successfully completed. www.cdhtz.com > update obj$ set name=’BOOTSTRAP_BACK’ where name=’BOOTSTRAP$’; 1 row updated. www.cdhtz.com > commit; Commit complete. www.cdhtz.com > shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. www.cdhtz.com > startup ORACLE instance started.
Total System Global Area 2137886720 bytes Fixed Size 2230072 bytes Variable Size 1493174472 bytes Database Buffers 637534208 bytes Redo Buffers 4947968 bytes Database mounted. Database opened. |
2 跟踪数据库开机读bootstrap$表
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BBED> set block 1 BLOCK# 1 BBED> map File: /oracle/app/oracle/oradata/orcl1123/system01.dbf (0) Block: 1 Dba:0x00000000 ———————————————————— Data File Header
struct kcvfh, 860 bytes @0
ub4 tailchk @8188
意思这里就是指定bootstrap$表存放的意思，我这里使用的htz表，事实的dba地址如下：方式二就是修改kcvfhrdb这个值。 BBED> p kcvfh BBED> p kcvfh.kcvfhrdb ub4 kcvfhrdb @96 0x00417648 www.cdhtz.com > @dba_to_fno_bno.sql Enter value for dba: 00417648
FILE BLOCK ———- ———- 1 95816
www.cdhtz.com > @segment.sql Enter value for owner: sys Enter value for segment_name: htz Enter value for tablespace_name:
HEADER OWNER:SEGMENT_NAME FILE_BLOCK ———————— ————– SYS.HTZ 1.95816 ****************************** Total:
1 row selected. www.cdhtz.com > alter system set db_file_multiblock_read_count=1; System altered. www.cdhtz.com > oradebug setmypid Statement processed. www.cdhtz.com > oradebug event 10046 trace name context forever,level 12; Statement processed. www.cdhtz.com > alter database open; Database altered. www.cdhtz.com > oradebug tracefile_name; /oracle/app/oracle/diag/rdbms/orcl1123/orcl1123/trace/orcl1123_ora_16641.trc
在trace文件中可以发现下面的内容 trace开头是读控制文件，读了控制文件后才读这个 WAIT #182936778744: nam=’control file sequential read’ ela= 5 file#=0 block#=1 blocks=1 obj#=-1 tim=1416412117362314 WAIT #182936778744: nam=’control file sequential read’ ela= 4 file#=0 block#=16 blocks=1 obj#=-1 tim=1416412117362330 WAIT #182936778744: nam=’control file sequential read’ ela= 3 file#=0 block#=18 blocks=1 obj#=-1 tim=1416412117362341 WAIT #182936778744: nam=’control file sequential read’ ela= 4 file#=0 block#=302 blocks=1 obj#=-1 tim=1416412117362354 WAIT #182936778744: nam=’instance state change’ ela= 796 layer=2 value=1 waited=1 obj#=-1 tim=1416412117363178 WAIT #182936778744: nam=’db file sequential read’ ela= 10 file#=1 block#=95816 blocks=1 obj#=-1 tim=1416412117363386 ===================== PARSING IN CURSOR #182937207776 len=193 dep=1 uid=0 oct=1 lid=0 tim=1416412117364049 hv=2050547241 ad=’de8496c0′ sqlid=’a6hh009x3jrj9′ 由于htz中已经删除了59这行的内容，不知道这条命令从那里来的，从oracle二进制文件中也没有找到。 create table bootstrap$ ( line# number not null, obj# number not null, sql_text varchar2(4000) not null) storage (initial 50K objno 82697 extents (file 1 block 95816)) END OF STMT PARSE #182937207776:c=0,e=573,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,plh=0,tim=1416412117364048 EXEC #182937207776:c=999,e=229,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,plh=0,tim=1416412117364312 CLOSE #182937207776:c=0,e=4,dep=1,type=0,tim=1416412117364370 ===================== PARSING IN CURSOR #182937207776 len=55 dep=1 uid=0 oct=3 lid=0 tim=1416412117364662 hv=2111436465 ad=’de8481d0′ sqlid=’6apq2rjyxmxpj’ select line#, sql_text from bootstrap$ where obj# != :1 END OF STMT PARSE #182937207776:c=0,e=279,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,plh=0,tim=1416412117364661 BINDS #182937207776: Bind#0 oacdty=02 mxl=22(22) mxlc=00 mal=00 scl=00 pre=00 oacflg=08 fl2=0001 frm=00 csi=00 siz=24 off=0 kxsbbbfp=2a97e83f98 bln=22 avl=04 flg=05 value=82697 EXEC #182937207776:c=1000,e=48132,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,plh=867914364,tim=1416412117412850 WAIT #182937207776: nam=’db file sequential read’ ela= 14 file#=1 block#=95816 blocks=1 obj#=82697 tim=1416412117412929 WAIT #182937207776: nam=’db file sequential read’ ela= 15 file#=1 block#=95817 blocks=1 obj#=82697 tim=1416412117413061 FETCH #182937207776:c=1000,e=300,p=2,cr=3,cu=0,mis=0,r=1,dep=1,og=4,plh=867914364,tim=1416412117413185 FETCH #182937207776:c=0,e=12,p=0,cr=1,cu=0,mis=0,r=1,dep=1,og=4,plh=867914364,tim=1416412117413231 FETCH #182937207776:c=0,e=5,p=0,cr=1,cu=0,mis=0,r=1,dep=1,og=4,plh=867914364,tim=1416412117413250 |
3 bbed修改
下面是bbed修改system文件头来实现切换bootstrap$
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www.htz.pw > select open_mode from v$database; OPEN_MODE ——————– READ WRITE www.htz.pw > create table htz as select * from bootstrap$; Table created. 这里记得删除obj#59不然会报错的，如下：
www.htz.pw > delete htz where obj#=59; 1 row deleted. www.htz.pw > commit; Commit complete. www.htz.pw > @extent.sql Enter value for owner: sys Enter value for segment_name: htz Enter value for tablespace_name:
FILE BLOCK OWNER:SEGMENT_NAME ID FNO EXTENT_ID BEGIN_END ——————– —– —– ———- ———— SYS.HTZ 1 1 0 86088~86095 ****************************** Total: 1 row selected. 转成DBA地址为00415048 www.htz.pw > @dba_to_fno_bno.sql Enter value for dba: 00415048 FILE BLOCK ———- ———- 1 86088 1 row selected www.htz.pw > select name from v$dbfile where file#=1; NAME ——————————————————————————– /oracle/app/oracle/oradata/orcl1123/system01.dbf
www.htz.pw > shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. 使用bbed修改kcvfhrdb的值 BBED> set filename ‘/oracle/app/oracle/oradata/orcl1123/system01.dbf’; FILENAME /oracle/app/oracle/oradata/orcl1123/system01.dbf
BBED> set block 1 BLOCK# 1
BBED> p kcvfh.kcvfhrdb ub4 kcvfhrdb @96 0x00400208
BBED> dump offset 96 count 20 File: /oracle/app/oracle/oradata/orcl1123/system01.dbf (0) Block: 1 Offsets: 96 to 115 Dba:0x00000000 ———————————————————————— 08024000 07000000 00000000 60776c2d 25f68233
<32 bytes per line>
BBED> set mode edit MODE Edit
BBED> set count 20 COUNT 20
BBED> modify /x 48504100 offset 96 Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y File: /oracle/app/oracle/oradata/orcl1123/system01.dbf (0) Block: 1 Offsets: 96 to 115 Dba:0x00000000 ———————————————————————— 48504100 07000000 00000000 60776c2d 25f68233
<32 bytes per line>
BBED> sum apply Check value for File 0, Block 1: current = 0xcebf, required = 0xcebf
BBED> verify DBVERIFY – Verification starting FILE = /oracle/app/oracle/oradata/orcl1123/system01.dbf BLOCK = 1
DBVERIFY – Verification complete
Total Blocks Examined : 1 Total Blocks Processed (Data) : 0 Total Blocks Failing (Data) : 0 Total Blocks Processed (Index): 0 Total Blocks Failing (Index): 0 Total Blocks Empty : 0 Total Blocks Marked Corrupt : 0 Total Blocks Influx : 0 Message 531 not found; product=RDBMS; facility=BBED
www.htz.pw > startup ORACLE instance started.
Total System Global Area 592920576 bytes Fixed Size 2230632 bytes Variable Size 176162456 bytes Database Buffers 411041792 bytes Redo Buffers 3485696 bytes Database mounted. Database opened. 数据库正常启动 www.htz.pw > oradebug setmypid Statement processed. www.htz.pw > oradebug event 10046 trace name context forever,level 12; Statement processed. www.htz.pw > show parameter db_file
NAME TYPE VALUE ———————————— ———– —————————— db_file_multiblock_read_count integer 128 db_file_name_convert string db_files integer 200 www.htz.pw > alter session set db_file_multiblock_read_count=1;
Session altered.
www.htz.pw > oradebug tracefile_name; /oracle/app/oracle/diag/rdbms/orcl1123/orcl1123/trace/orcl1123_ora_20077.trc www.htz.pw > alter database open;
Database altered.
在trace文件中可以看到下面的信息 WAIT #182936774688: nam=’db file sequential read’ ela= 10 file#=1 block#=86088 blocks=1 obj#=-1 tim=1416570843425508 ===================== PARSING IN CURSOR #182937313288 len=193 dep=1 uid=0 oct=1 lid=0 tim=1416570843426130 hv=819885117 ad=’830e4b60′ sqlid=’g63vpahsdwx1x’ create table bootstrap$ ( line# number not null, obj# number not null, sql_text varchar2(4000) not null) storage (initial 50K objno 75577 extents (file 1 block 86088)) END OF STMT PARSE #182937313288:c=999,e=544,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,plh=0,tim=1416570843426129 EXEC #182937313288:c=0,e=153,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,plh=0,tim=1416570843426318 CLOSE #182937313288:c=0,e=5,dep=1,type=0,tim=1416570843426373 |
再次申明：只能在测试环境玩玩，生产环境千万不要玩这些，也没有实际的作用。
substituter bootstrap$ using other table：等您坐沙发呢！