总结：IMU模式下DML语句所产生的REDO RECORD式，是先有操作的 change rector，再有向向UNDO段头的事务表写事务信息的change rector，再提交操作的change rector后，才进行把数据修改前放到UNDO的change rector。 注意：实验中INSERT和DELETE是先后做的，UPDAT
总结：IMU模式下DML语句所产生的REDO RECORD格式，是先有操作的 change rector，再有向向UNDO段头的事务表写事务信息的change rector，再提交操作的change rector后，才进行把数据修改前值放到UNDO的change rector。
注意：实验中INSERT和DELETE是先后做的，UPDATE操作是其它时间做的，UPDATE实验时的表数据和另两步不一样。
DML操作的change rector产生顺序汇总如下： --DML实验及DUMP的REDO日志见下面具体实验步骤。
INSERT --涉及有索引的字段
CHANGE #1 OP:11.2 --插入操作
CHANGE #2 OP:5.2 --operation code 向UNDO段头的事务表写事务信息-事务开始
CHANGE #3 OP:10.2 --10.2 是插入索引叶子块
CHANGE #4 OP:5.4 ----提交
CHANGE #5 OP:5.1 --把表内数据修改前值放到UNDO--objn: 22327，插入的表的对象ID。
CHANGE #6 OP:5.1 --把索引数据修改前值放到UNDO--objn: 22818，索引对象ID。
一条INSERT语句为什么写了两次OP:5.1操作，是因为存在索引。
#################
UPDATE：--这个操作没涉及索引的字段
CHANGE#1 OP:11.19 --或者OP:11.5都是--UPDATE语句，开始修改数据，
CHANGE#2 OP:5.2 --operation code 向UNDO段头的事务表写事务信息-事务开始
CHANGE#3 OP:11.19 --或者OP:11.5都是--UPDATE语句，开始修改数据，
CHANGE #4 OP:5.4 --提交
CHANGE #5 OP:5.1 --把表内数据修改前值放到UNDO
CHANGE #6 OP:5.1 --把表内数据修改前值放到UNDO
################
DELETE: --涉及有索引的字段
CHANGE #1 OP:11.3 --DELETE语句的操作
CHANGE #2 OP:5.2 --operation code 向UNDO段头的事务表写事务信息-事务开始
CHANGE #3 OP:10.4 --删除索引叶子块
CHANGE #4 OP:5.4 --提交
CHANGE #5 OP:5.1 --把表内数据修改前值放到UNDO
CHANGE #6 OP:5.1 --把索引数据修改前值放到UNDO
一条DELETE语句为什么写了两次OP:5.1操作，是因为存在索引。
以上INSERT及DELETE时涉及的对索引的操作，如表上无索引，将涉及索引的CHANGE #条目去除，就是正常的CHANGE 产生顺序。
具体实验详情如下：--确保环境已经改为使用IMU。alter system set "_in_memory_undo"=true;
insert操作：
SYS@ bys3>alter system switch logfile;
System altered.
SYS@ bys3>col MEMBER for a30
SYS@ bys3>select a.group#,a.sequence#,a.archived,a.status,b.type,b.member from v$log a,v$logfile b where a.group#=b.group#;
GROUP# SEQUENCE# ARC STATUS TYPE MEMBER
---------- ---------- --- ---------------- ------- ------------------------------
1 322 YES INACTIVE ONLINE /u01/oradata/bys3/redo01.log
2 323 YES ACTIVE ONLINE /u01/oradata/bys3/redo02.log
3 324 NO CURRENT ONLINE /u01/oradata/bys3/redo03.log
SYS@ bys3>conn bys/bys
Connected.
BYS@ bys3>select * from dept;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
40 OPERATIONS BOSTON
11 database bj
22 dataoracle sh
BYS@ bys3>select a.index_owner,a.index_name,b.object_id,a.table_owner,a.table_name,a.column_name from all_ind_columns a,dba_objects b where a.index_owner='BYS' and a.index_name=b.object_name;
INDEX_OWNE INDEX_NAME OBJECT_ID TABLE_OWNE TABLE_NAME COLUMN_NAM
---------- ---------- ---------- ---------- ------------------------------ ----------
BYS INDTEXT
22818 BYS DEPT DEPTNO
BYS@ bys3>set time on
19:35:01 BYS@ bys3>insert into dept values(66,'imutest2','zhengzhou');
1 row created.
19:35:33 BYS@ bys3>commit;
Commit complete.
19:35:40 BYS@ bys3>
另一会话：
BYS@ bys3>alter system dump logfile '/u01/oradata/bys3/redo03.log';
System altered.
BYS@ bys3>select value from v$diag_info where name like 'De%' ;
VALUE
----------------------------------------------------------------------------------------------------
/u01/diag/rdbms/bys3/bys3/trace/bys3_ora_28763.trc
BYS@ bys3>select chr(to_number(substr(replace('c1 43',' '),rownum*2-1,2),'xxxxxxxx')),chr(to_number(substr(replace('69 6d 75 74 65 73 74 32',' '),rownum*2-1,2),'xxxxxxxx')),chr(to_number(substr(replace('7a 68 65 6e 67 7a 68 6f 75',' '),rownum*2-1,2),'xxxxxxxx'))
from v$bh where rownum<9;
CHR( CHR( CHR(
---- ---- ----
? i z
C m h
u e
t n
e g
s z
t h
2 o
#####################################
REDO RECORD - Thread:1 RBA: 0x000144.0000000e.0010 LEN: 0x02e4 VLD: 0x0d
SCN: 0x0000.00729c6b SUBSCN: 1 01/08/2014 19:35:40
(LWN RBA: 0x000144.0000000e.0010 LEN: 0002 NST: 0001 SCN: 0x0000.00729c6a)
#######一个REDO RECORD: RECORD头+CHANGE VECTOR组成（一个CV就是一个操作）
以上是日志头,Thread:1 线程号，RAC时会有1，2等
BA: 0x000144.0000000e.0010 将16进制转换为十进制分别是日志文件号、日志块号、在块上第N字节
VLD: 0x0d日志类型--IMU模式时是这个；非IMU时是：VLD: 0x05
SCN: 0x0000.00729c6b SUBSCN: 1 01/08/2014 19:35:40
BYS@ bys3>select scn_to_timestamp(to_number('729c6b','xxxxxxxx')) from dual;
SCN_TO_TIMESTAMP(TO_NUMBER('729C6B','XXXXXXXX'))
---------------------------------------------------------------------------
08-JAN-14 07.35.38.000000000 PM
--是此REDO条目产生时的SCN号，转为十进制现转为时间戳为：19:35:33， 插入语句完成是在19:35:33 BYS@ bys3>commit;
(LWN RBA: 0x000144.0000000e.0010 LEN: 0002 NST: 0001 SCN: 0x0000.00729c6a)
括号中SCN: 0x0000.00729c6a 比上一行：SCN: 0x0000.00729c6b 少了1个SCN。
################
CHANGE #1 TYP:2 CLS:1 AFN:4 DBA:0x010000fd OBJ:22327 SCN:0x0000.00719188 SEQ:3OP:11.2 ENC:0 RBL:0
##AFN:4，操作是在4号文件做的-dba_data_files.file_id；OBJ:22327--操作的对象的OBJECT_ID。OP:11.2--插入操作
KTB Redo
op: 0x01 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x0001.00f.00000f13 uba: 0x00c017b7.0262.08
KDO Op code: IRP row dependencies Disabled --这个是IRP --INSERT ROW PIECE
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 1 ispac: 0 maxfr: 4858
tabn: 0 slot: 2(0x2) size/delt: 25
fb: --H-FL-- lb: 0x1 cc: 3
null: ---
col 0: [ 2] c1 43 --col 0: [ 2]，第一列，2个字符
col 1: [ 8] 69 6d 75 74 65 73 74 32 --第2列，8个字符
col 2: [ 9] 7a 68 65 6e 67 7a 68 6f 75
#####可以将插入的值转为16进制，可以与这里的值对应上。
insert into dept values(66,'imutest2','zhengzhou');
BYS@ bys3>select dump('66',16),dump('imutest2',16),dump('zhengzhou',16) from dual;
DUMP('66',16) DUMP('IMUTEST2',16) DUMP('ZHENGZHOU',16)
------------------- ------------------------------------- ----------------------------------------
Typ=96 Len=2: 36,36 Typ=96 Len=8: 69,6d,75,74,65,73,74,32 Typ=96 Len=9: 7a,68,65,6e,67,7a,68,6f,75
CHANGE #2 TYP:0 CLS:17 AFN:3 DBA:0x00c00080 OBJ:4294967295 SCN:0x0000.00729c37 SEQ:2OP:5.2 ENC:0 RBL:0
ktudh redo: slt: 0x000f sqn: 0x00000f13 flg: 0x0012 siz: 136 fbi: 0 ---OP:5.2，向UNDO段头的事务表写事务信息-事务开始
uba: 0x00c017b7.0262.08 pxid: 0x0000.000.00000000
CHANGE #3 TYP:0 CLS:1 AFN:4 DBA:0x01003d53 OBJ:22818 SCN:0x0000.00729c68 SEQ:1 OP:10.2 ENC:0 RBL:0
index redo (kdxlin): insert leaf row --也说明是向索引插入，OBJ:22818就是索引的对象ID，OP:10.2-插入索引叶子块
KTB Redo
op: 0x01 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x0001.00f.00000f13 uba: 0x00c017b7.0262.09
REDO: SINGLE / -- / --
itl: 2, sno: 5, row size 14
insert key: (10): 02 c1 43 06 01 00 00 fd 00 02 --向索引叶子插入的KEY值
CHANGE #4 TYP:0 CLS:17 AFN:3 DBA:0x00c00080 OBJ:4294967295 SCN:0x0000.00729c6b SEQ:1OP:5.4 ENC:0 RBL:0
ktucm redo: slt: 0x000f sqn: 0x00000f13 srt: 0 sta: 9 flg: 0x2 ktucf redo: uba: 0x00c017b7.0262.09 ext: 3 spc: 7012 fbi: 0
###OP:5.4 --在这个CHANGE #4中对此事务做了提交操作
CHANGE #5 TYP:0 CLS:18 AFN:3 DBA:0x00c017b7 OBJ:4294967295 SCN:0x0000.00729c37 SEQ:3 OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 136 spc: 7252 flg: 0x0012 seq: 0x0262 rec: 0x08 ----OP:5.1-数据修改前值放到UNDO
xid: 0x0001.00f.00000f13
ktubl redo: slt: 15 rci: 0 opc: 11.1 [objn: 22327 objd: 22327 tsn: 4] --是对表内数据的
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
0x00000000 prev ctl uba: 0x00c017b7.0262.05
prev ctl max cmt scn: 0x0000.00729783 prev tx cmt scn: 0x0000.0072978f
txn start scn: 0x0000.00729c68 logon user: 32 prev brb: 12588976 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: 0x0005.005.00000ed4 uba: 0x00c029f3.02e9.0e
flg: C--- lkc: 0 scn: 0x0000.007164a1
KDO Op code: DRP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 1 ispac: 0 maxfr: 4858
tabn: 0 slot: 2(0x2)
CHANGE #6 TYP:0 CLS:18 AFN:3 DBA:0x00c017b7 OBJ:4294967295 SCN:0x0000.00729c6b SEQ:1 OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 100 spc: 7114 flg: 0x0022 seq: 0x0262 rec: 0x09
xid: 0x0001.00f.00000f13
ktubu redo: slt: 15 rci: 8 opc: 10.22 objn: 22818 objd: 22818 tsn: 4 ---objn: 22818是索引的OBJECT_ID
Undo type: Regular undo Undo type: Last buffer split: No
Tablespace Undo: No
0x00000000
index undo for leaf key operations
KTB Redo
op: 0x04 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: L itl: xid: 0x0005.005.00000ed4 uba: 0x00c029f3.02e9.0f
flg: C--- lkc: 0 scn: 0x0000.007164a1
Dump kdilk : itl=2, kdxlkflg=0x1 sdc=1 indexid=0x1003d52 block=0x01003d53
(kdxlpu): purge leaf row ----这里的purge leaf row也证明了CHANGE #6这个是对索引的操作
key :(10): 02 c1 43 06 01 00 00 fd 00 02
END OF REDO DUMP
#################################################################
UPDATE操作：
明天补。。
###################################################################
DELETE操作：
SYS@ bys3>alter system switch logfile;
System altered.
SYS@ bys3>select a.group#,a.sequence#,a.archived,a.status,b.type,b.member from v$log a,v$logfile b where a.group#=b.group#;
GROUP# SEQUENCE# ARC STATUS TYPE MEMBER
---------- ---------- --- ---------------- ------- ------------------------------
1 325 NO CURRENT ONLINE /u01/oradata/bys3/redo01.log
2 323 YES INACTIVE ONLINE /u01/oradata/bys3/redo02.log
3 324 YES ACTIVE ONLINE /u01/oradata/bys3/redo03.log
SYS@ bys3>conn bys/bys
Connected.
BYS@ bys3>select * from dept;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
66 imutest2 zhengzhou
40 OPERATIONS BOSTON
11 database bj
22 dataoracle sh
BYS@ bys3>set time on
20:32:58 BYS@ bys3>delete dept where deptno=66;
1 row deleted.
20:33:02 BYS@ bys3>commit;
Commit complete.
20:33:06 BYS@ bys3>
另一会话DUMP REDO LOGFILE:
BYS@ bys3>alter system dump logfile '/u01/oradata/bys3/redo01.log';
System altered.
BYS@ bys3>select value from v$diag_info where name like 'De%' ;
VALUE
----------------------------------------------------------------------------------------------------
/u01/diag/rdbms/bys3/bys3/trace/bys3_ora_29403.trc
#######################
REDO RECORD - Thread:1 RBA: 0x000145.00000003.0010 LEN: 0x0308 VLD: 0x0d
SCN: 0x0000.0072a6f2 SUBSCN: 1 01/08/2014 20:33:06
(LWN RBA: 0x000145.00000003.0010 LEN: 0002 NST: 0001 SCN: 0x0000.0072a6f1)
CHANGE #1 TYP:2 CLS:1 AFN:4 DBA:0x010000fd OBJ:22327 SCN:0x0000.00729c6b SEQ:2 OP:11.3 ENC:0 RBL:0
KTB Redo
op: 0x11 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x000a.002.00000f0c uba: 0x00c0175c.026f.01
Block cleanout record, scn: 0x0000.0072a6ee ver: 0x01 opt: 0x02, entries follow...
itli: 1 flg: 2 scn: 0x0000.00729c6b
itli: 2 flg: 2 scn: 0x0000.00719188
KDO Op code: DRP row dependencies Disabled --DRP DROP ROW PIECE
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 2(0x2)
CHANGE #2 TYP:0 CLS:35 AFN:3 DBA:0x00c00110 OBJ:4294967295 SCN:0x0000.0072a6b9 SEQ:1 OP:5.2 ENC:0 RBL:0
ktudh redo: slt: 0x0002 sqn: 0x00000f0c flg: 0x000a siz: 200 fbi: 0
uba: 0x00c0175c.026f.01 pxid: 0x0000.000.00000000
CHANGE #3 TYP:0 CLS:1 AFN:4 DBA:0x01003d53 OBJ:22818 SCN:0x0000.0072a6ef SEQ:1OP:10.4 ENC:0 RBL:0
index redo (kdxlde): delete leaf row ---删除索引叶
KTB Redo
op: 0x01 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x000a.002.00000f0c uba: 0x00c0175c.026f.02
REDO: SINGLE / -- / --
itl: 2, sno: 5, row size 14
CHANGE #4 TYP:0 CLS:35 AFN:3 DBA:0x00c00110 OBJ:4294967295 SCN:0x0000.0072a6f2 SEQ:1OP:5.4 ENC:0 RBL:0
ktucm redo: slt: 0x0002 sqn: 0x00000f0c srt: 0 sta: 9 flg: 0x2 ktucf redo: uba: 0x00c0175c.026f.02 ext: 4 spc: 7846 fbi: 0
CHANGE #5 TYP:1 CLS:36 AFN:3 DBA:0x00c0175c OBJ:4294967295 SCN:0x0000.0072a6ee SEQ:1OP:5.1
ENC:0 RBL:0
ktudb redo: siz: 200 spc: 0 flg: 0x000a seq: 0x026f rec: 0x01
xid: 0x000a.002.00000f0c
ktubl redo: slt: 2 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: 0x00c0175b.026f.07
prev ctl max cmt scn: 0x0000.0072a2c6 prev tx cmt scn: 0x0000.0072a2d5
txn start scn: 0x0000.0072a6ef logon user: 32 prev brb: 12588886 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: 0x0005.002.00000edc uba: 0x00c041cd.02ea.02
flg: C--- lkc: 0 scn: 0x0000.00719188
KDO Op code: IRP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x010000fd hdba: 0x010000fa
itli: 2 ispac: 0 maxfr: 4858
tabn: 0 slot: 2(0x2) size/delt: 25
fb: --H-FL-- lb: 0x0 cc: 3
null: ---
col 0: [ 2] c1 43 --这三行是删除前的值，参见第一步INSERT里的DUMP计算
col 1: [ 8] 69 6d 75 74 65 73 74 32
col 2: [ 9] 7a 68 65 6e 67 7a 68 6f 75
#####可以将第一步插入的值转为16进制，可以与这里的值对应上。 -- 66 imutest2 zhengzhou
BYS@ bys3>select dump('66',16),dump('imutest2',16),dump('zhengzhou',16) from dual;
DUMP('66',16) DUMP('IMUTEST2',16) DUMP('ZHENGZHOU',16)
------------------- ------------------------------------- ----------------------------------------
Typ=96 Len=2: 36,36 Typ=96 Len=8: 69,6d,75,74,65,73,74,32 Typ=96 Len=9: 7a,68,65,6e,67,7a,68,6f,75
CHANGE #6 TYP:0 CLS:36 AFN:3 DBA:0x00c0175c OBJ:4294967295 SCN:0x0000.0072a6f2 SEQ:1OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 100 spc: 7948 flg: 0x0022 seq: 0x026f rec: 0x02
xid: 0x000a.002.00000f0c
ktubu redo: slt: 2 rci: 1 opc: 10.22 objn: 22818 objd: 22818 tsn: 4
Undo type: Regular undo Undo type: Last buffer split: No
Tablespace Undo: No
0x00000000
index undo for leaf key operations ---索引叶子值的UNDO
KTB Redo
op: 0x04 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: L itl: xid: 0x0001.00f.00000f13 uba: 0x00c017b7.0262.09
flg: C--- lkc: 0 scn: 0x0000.00729c6b
Dump kdilk : itl=2, kdxlkflg=0x1 sdc=0 indexid=0x1003d52 block=0x01003d53
(kdxlre): restore leaf row (clear leaf delete flags) --这个CHANGE #6往UNDO里写恢复索引叶子的，
key :(10): 02 c1 43 06 01 00 00 fd 00 02
