崩溃恢复的起点和终点(四)
所以它就是数据文件中恢复的起点
然后我们看看数据文件中的Thread Checkpoint RBA ：00000025.00000042.047e0010
转换过来就是Low Cache RBA的logfile sequence是37，logfile block number是66。
SESSION A>select to_number('25','XXXXXXXX') from dual;
TO_NUMBER('25','XXXXXXXX')
--------------------------
37
SESSION A>
SESSION A>select to_number('42','XXXXXXXX') from dual;
TO_NUMBER('42','XXXXXXXX')
--------------------------
66
我们可以看到现在控制文件里记录的On Disk RBA是0x25.49.0，转换过来就是On Disk RBA的logfile sequence是37，logfile block number是73：
SESSION A>select to_number('25','XXXXXXXX') from dual;
TO_NUMBER('25','XXXXXXXX')
--------------------------
37
SESSION A>
SESSION A>select to_number('48','XXXXXXXX') from dual;
TO_NUMBER('49','XXXXXXXX')
--------------------------
72
然后我们看看redolog中的信息，首先来看current redo log file的尾端的插入记录：
REDO RECORD - Thread:1 RBA: 0x000025.00000049.0010 LEN: 0x01f0 VLD: 0x0d
SCN: 0x0000.00199bed SUBSCN: 1 04/26/2013 14:19:10
(LWN RBA: 0x000025.00000049.0010 LEN: 0001 NST: 0001 SCN: 0x0000.00199bec)
CHANGE #1 TYP:2 CLS:1 AFN:5 DBA:0x0140000d OBJ:75987 SCN:0x0000.00199beb SEQ:2 OP:11.2 ENC:0 RBL:0
KTB Redo
op: 0x01 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x0003.00f.00000396 uba: 0x00c00632.00de.0e
KDO Op code: IRP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0140000d hdba: 0x0140000a
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 31(0x1f) size/delt: 6
fb: --H-FL-- lb: 0x2 cc: 1
null: -
col 0: [ 2] c1 21
CHANGE #2 TYP:0 CLS:21 AFN:3 DBA:0x00c000a0 OBJ:4294967295 SCN:0x0000.00199be9 SEQ:2 OP:5.2 ENC:0 RBL:0
ktudh redo: slt: 0x000f sqn: 0x00000396 flg: 0x0012 siz: 136 fbi: 0
uba: 0x00c00632.00de.0e pxid: 0x0000.000.00000000
CHANGE #3 TYP:0 CLS:21 AFN:3 DBA:0x00c000a0 OBJ:4294967295 SCN:0x0000.00199bed SEQ:1 OP:5.4 ENC:0 RBL:0
ktucm redo: slt: 0x000f sqn: 0x00000396 srt: 0 sta: 9 flg: 0x2 ktucf redo: uba: 0x00c00632.00de.0e ext: 2 spc: 6314 fbi: 0
CHANGE #4 TYP:0 CLS:22 AFN:3 DBA:0x00c00632 OBJ:4294967295 SCN:0x0000.00199be9 SEQ:1 OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 136 spc: 6452 flg: 0x0012 seq: 0x00de rec: 0x0e
xid: 0x0003.00f.00000396
ktubl redo: slt: 15 rci: 0 opc: 11.1 [objn: 75987 objd: 75987 tsn: 6]
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
0x00000000 prev ctl uba: 0x00c00632.00de.0d
prev ctl max cmt scn: 0x0000.00194640 prev tx cmt scn: 0x0000.00194645
txn start scn: 0x0000.00199beb logon user: 0 prev brb: 12584496 prev bcl: 0 BuExt idx: 0 flg2: 0
KDO undo record:
KTB Redo
op: 0x04 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: L itl: xid: 0x0003.005.00000395 uba: 0x00c00632.00de.0d
flg: C--- lkc: 0 scn: 0x0000.00199be9
KDO Op code: DRP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0140000d hdba: 0x0140000a
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 31(0x1f)
SESSION A> select owner,object_name from dba_objects where object_id=75987;
OWNER OBJECT_NAME
------------------------------ ------------------------------
SYS T
SQL> select utl_raw.