关于SMON每三秒从IMU中拷贝修改前值到BUFFERCACHE中构建一个CR块

借老郭的上图，说明一下： vcD4KPGgzPlVQREFURdPvvuS007Xa0ruyvbW9tdq+xbK9tcS21NOmysejujwvaDM+CrXa0ruyvaO6vau4/LjEtcTK/b7dtOa3xbW9UEdBICA8YnI+CrXatv6yvaO6vatCVUZGRVIgQ0FDSEXW0L7Jyv2+3b+9sbS1vbmyz+2z2LXEy73T0ElNVSBidWZmZXI8YnI+CrXayP2yvaO6vatQR

借老郭的上图，说明一下：喎?http://www.2cto.com/kf/ware/vc/" target="_blank" class="keylink">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"mysql' where deptno=11;
1 row updated.
Elapsed: 00:00:00.01

12:12:29 BYS@ bys3> ---UPDATE语句完成的时间是：12:12:29，只做UPDATE语句，不要提交，立刻去DUMP REDO LOGFILE.

执行完此操作迅速（3秒内）的进行DUMP REDO LOGFILE的操作，从DUMP出的文件中，是找不到此事务的REDO日志条目。有兴趣的可以做一下试试。

如果过3秒后，再执行DUMP REDO LOGFILE的操作，从DUMP出的文件中，可以看到此次操作的信息：--怎么感觉这样不太严谨

REDO RECORD - Thread:1 RBA: 0x00014e.0000000e.0010 LEN: 0x01bc VLD: 0x0d

SCN: 0x0000.00736971 SUBSCN: 1 01/09/2014 12:12:31 --时间与12:12:29对比，刚好是3秒，但是这一点好像不绝对，其它实验中有间隔5秒直到发出COMMIT才产生日志的。--不确定看这个地方对不对呢？
(LWN RBA: 0x00014e.0000000e.0010 LEN: 0003 NST: 0001 SCN: 0x0000.00736971)
CHANGE #1 TYP:0 CLS:1 AFN:4 DBA:0x010000fd OBJ:22327 SCN:0x0000.00736959 SEQ:2 OP:11.5 ENC:0 RBL:0
KTB Redo
op: 0x01 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x0007.020.00000f43 uba: 0x00c02059.02c8.0c
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 8(0x8) flag: 0x2c lock: 2 ckix: 0
ncol: 3 nnew: 1 size: -3
col 1: [ 5] 6d 79 73 71 6c
CHANGE #2 TYP:0 CLS:29 AFN:3 DBA:0x00c000e0 OBJ:4294967295 SCN:0x0000.0073692e SEQ:2 OP:5.2 ENC:0 RBL:0
ktudh redo: slt: 0x0020 sqn: 0x00000f43 flg: 0x0012 siz: 164 fbi: 0
uba: 0x00c02059.02c8.0c pxid: 0x0000.000.00000000
CHANGE #3 TYP:0 CLS:30 AFN:3 DBA:0x00c02059 OBJ:4294967295 SCN:0x0000.0073692e SEQ:3 OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 164 spc: 6772 flg: 0x0012 seq: 0x02c8 rec: 0x0c
xid: 0x0007.020.00000f43
ktubl redo: slt: 32 rci: 0 opc: 11.1 [objn: 22327 objd: 22327 tsn: 4]
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
0x00000000 prev ctl uba: 0x00c02059.02c8.09
prev ctl max cmt scn: 0x0000.007365f2 prev tx cmt scn: 0x0000.00736612
txn start scn: 0x0000.007368a2 logon user: 32 prev brb: 12591190 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: 0x000a.002.00000f0c uba: 0x00c0175c.026f.01
flg: C--- lkc: 0 scn: 0x0000.0072a6f2
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 8(0x8) flag: 0x2c lock: 0 ckix: 0
ncol: 3 nnew: 1 size: 3
col 1: [ 8] 64 61 74 61 62 61 73 65