Oracle数据库中独一无二的Cache对象

核心提示： 这个root dba：0x004001a1 正好指向的是file 1 block 417而我们dump file 1 block 417就可以找到bootstrap$的地址：Start dump data blocks tsn: 0 file#: 1 minblk 417 maxblk 4

这个root dba：0x004001a1 正好指向的是file 1 block 417而我们dump file 1 block 417就可以找到bootstrap$的地址：

Start dump data blocks tsn: 0 file#: 1 minblk 417 maxblk 419
buffer tsn: 0 rdba: 0x004001a1 (1/417)
scn: 0x0004.6c47f014 seq: 0x01 flg: 0x04 tail: 0xf0140d01
frmt: 0x02 chkval: 0xa59e type: 0x0d=Compatibility segment
Header:　size 12　next rdba 0x0　entries 25　offset 536f
Compatibility entry for 'COMPATSG':
　Size: 24　Release 0x134217728　By 0x153092096
Dump of memory from 0x0AA84E34 to 0x0AA84E38
AA84E30　　　　　00000000　　　　　　　　　　　　[....]　　　　
Compatibility entry for 'BOOTSTRP':
　Size: 24　Release 0x134217728　By 0x153092096
Dump of memory from 0x0AA84E4C to 0x0AA84E50
AA84E40　　　　　　　　　　　　　　00400179　　　　　　 [y.@.]
Compatibility entry for 'UNDODATA':
　Size: 36　Release 0x153092096　By 0x153092096
Dump of memory from 0x0AA84E64 to 0x0AA84E74
AA84E60　　　　　00000042 5221003E 6C47F00D　　　[B...>.!R..Gl]
AA84E70 00000004　　　　　　　　　　　　　　[....]

dba号00400179 正好指向的file 1 block 377。

在Oracle10g中，Oracle将这个root dba更改得更为直接：

DATA FILE #1:
　(name #7) +ORADG/danaly/datafile/system.264.600173859
creation size=38400 block size=8192 status=0xe head=7 tail=7 dup=1
tablespace 0, index=1 krfil=1 prev_file=0
unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
Checkpoint cnt:45507 scn: 0x081a.88397cdd 04/19/2007 10:36:17
Stop scn: 0xffff.ffffffff 01/27/2007 17:56:34
Creation Checkpointed at scn:　0x0000.00000007 09/03/2006 10:57:47
thread:1 rba:(0x1.3.10)
enabled　threads:　01000000 00000000 00000000 00000000 00000000 00000000
　00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
　00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x0000.00000000 prev_range: 0
Online Checkpointed at scn:　0x0000.00000000
thread:0 rba:(0x0.0.0)
enabled　threads:　00000000 00000000 00000000 00000000 00000000 00000000
　00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
　00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000.00000000
aux_file is NOT DEFINED
V10 STYLE FILE HEADER:
　　　　Compatibility Vsn = 169869568=0xa200100
　　　　Db ID=3965153484=0xec5770cc, Db Name='DANALY'
　　　　Activation ID=0=0x0
　　　　Control Seq=2912565=0x2c7135, File size=84180=0x148d4
　　　　File Number=1, Blksiz=8192, File Type=3 DATA
Tablespace #0 - SYSTEM　rel_fn:1
Creation　at　scn: 0x0000.00000007 09/03/2006 10:57:47
Backup taken at scn: 0x0000.00000000 01/01/1988 00:00:00 thread:0
reset logs count:0x23c5ed0c scn: 0x0000.00000001
reset logs terminal rcv data:0x0 scn: 0x0000.00000000
prev reset logs count:0x0 scn: 0x0000.00000000 prev
reset logs terminal rcv data:0x0 scn: 0x0000.00000000
recovered at 01/28/2007 21:29:12
status:0x2004 root dba:0x00400179 chkpt cnt: 45507 ctl cnt:45506
begin-hot-backup file size: 0