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2#
发表于 2013-3-31 14:41:24
1 KTU UNDO HEADER
SQL> select file_id,blocks,TABLESPACE_NAME from dba_data_Files;
FILE_ID BLOCKS TABLESPACE_NAME
---------- ---------- ------------------------------
6 54560 USERS
4 40320 UNDOTBS1
3 99840 SYSAUX
1 122880 SYSTEM
15 1280 CCF_SNDPAYLIST
16 6400 UNDOTBS2
17 3840 LV
SQL> oradebug setmypid
Statement processed.
SQL> oradebug tracefile_name
/u01/app/oracle/diag/rdbms/cdb1/cdb1/trace/cdb1_ora_26286.trc
SQL> alter system dump datafile 16 block min 0 block max 6400;
System altered.
Block dump from disk:
buffer tsn: 5 rdba: 0x04000080 (16/128)
scn: 0x0000.00516cf8 seq: 0x01 flg: 0x04 tail: 0x6cf82601
frmt: 0x02 chkval: 0x73d2 type: 0x26=KTU SMU HEADER BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00007FD992B8FE00 to 0x00007FD992B91E00
Extent Control Header
-----------------------------------------------------------------
Extent Header:: spare1: 0 spare2: 0 #extents: 5 #blocks: 39
last map 0x00000000 #maps: 0 offset: 4080
Highwater:: 0x04000195 ext#: 3 blk#: 5 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 0
mapblk 0x00000000 offset: 3
Unlocked
Map Header:: next 0x00000000 #extents: 5 obj#: 0 flag: 0x40000000
Extent Map
-----------------------------------------------------------------
0x04000081 length: 7
0x04000088 length: 8
0x04000138 length: 8
0x04000190 length: 8
0x04000200 length: 8
>>>> 这里上面是Extent盘区控制头, 5个extent 39个block
Retention Table
-----------------------------------------------------------
Extent Number:0 Commit Time: 1364178671
Extent Number:1 Commit Time: 1364371676
Extent Number:2 Commit Time: 1364697013
Extent Number:3 Commit Time: 1364697013
Extent Number:4 Commit Time: 0
>>>> Retention Table是 undo segment header的一部分, 这个 Retention Table 记录了2个因素:
1. Extent Number 盘区号
2. commit time提交时间, 这个提交时间是使用该extent的最后一个事务的提交SCN。
TRN CTL:: seq: 0x0004 chd: 0x0002 ctl: 0x0001 inc: 0x00000000 nfb: 0x0001
mgc: 0xb000 xts: 0x0068 flg: 0x0001 opt: 2147483646 (0x7ffffffe)
uba: 0x04000195.0004.25 scn: 0x0000.00515849
SEQ==>该undo segment最后一个block的sequence号
UBA(Control UBA) , 指的是用来回滚该TX table的undo记录对应的UBA
SCN(Control SCN),最近从事务表中迁出事务的commit scn号
CHD (Commit Head) , chd指向该事务表中下一个可以被重新利用的slot 0x0002
ctl (commit tail),指向事务表中最新commit的记录。 0x0001
INC incarnation的高水位号
NFB 表示free block pool中非空block的数目
MGC 用来测试一致性的
OPT 是rollback segment的OPTIMIAL 参数
Version: 0x01
FREE BLOCK POOL::
uba: 0x04000195.0004.3f ext: 0x3 spc: 0x234
uba: 0x00000000.0004.01 ext: 0x3 spc: 0x1f84
uba: 0x00000000.0003.08 ext: 0x2 spc: 0x1902
uba: 0x00000000.0000.00 ext: 0x0 spc: 0x0
uba: 0x00000000.0000.00 ext: 0x0 spc: 0x0
TRN TBL::
index state cflags wrap# uel scn dba parent-xid nub stmt_num cmt
------------------------------------------------------------------------------------------------
0x00 9 0x00 0x0011 0x0001 0x0000.00516ce7 0x04000195 0x0000.000.00000000 0x00000001 0x00000000 1364711255
0x01 9 0x00 0x0011 0xffff 0x0000.00516cf8 0x04000195 0x0000.000.00000000 0x00000001 0x00000000 1364711255
0x02 9 0x00 0x0010 0x0003 0x0000.00515aea 0x04000193 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x03 9 0x00 0x0010 0x0004 0x0000.00515afa 0x04000193 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x04 9 0x00 0x0010 0x0005 0x0000.00515b04 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x05 9 0x00 0x0010 0x0006 0x0000.00515b1d 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x06 9 0x00 0x0010 0x0007 0x0000.00515b30 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x07 9 0x00 0x0010 0x0008 0x0000.00515b44 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x08 9 0x00 0x0010 0x0009 0x0000.00515b58 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x09 9 0x00 0x0010 0x000a 0x0000.00515b6c 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0a 9 0x00 0x0010 0x000b 0x0000.00515b80 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0b 9 0x00 0x0010 0x000c 0x0000.00515b93 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0c 9 0x00 0x0010 0x000d 0x0000.00515ba7 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0d 9 0x00 0x0010 0x000e 0x0000.00515bba 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0e 9 0x00 0x0010 0x000f 0x0000.00515bce 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x0f 9 0x00 0x0010 0x0010 0x0000.00515be0 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x10 9 0x00 0x0010 0x0011 0x0000.00515bef 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364706745
0x11 9 0x00 0x0010 0x0014 0x0000.00515d00 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707047
0x12 9 0x00 0x0010 0x0015 0x0000.00515f61 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707646
0x13 9 0x00 0x0010 0x0012 0x0000.00515ee9 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707529
0x14 9 0x00 0x0010 0x0013 0x0000.00515e0c 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707342
0x15 9 0x00 0x0010 0x0016 0x0000.00515f6b 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707646
0x16 9 0x00 0x0010 0x0017 0x0000.00515fd1 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707710
0x17 9 0x00 0x0010 0x0018 0x0000.00516080 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364707891
0x18 9 0x00 0x0010 0x0019 0x0000.0051612f 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364708073
0x19 9 0x00 0x0010 0x001a 0x0000.005161de 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364708254
0x1a 9 0x00 0x0010 0x001b 0x0000.005162ca 0x04000194 0x0000.000.00000000 0x00000001 0x00000000 1364708542
0x1b 9 0x00 0x0010 0x001c 0x0000.005162df 0x04000195 0x0000.000.00000000 0x00000001 0x00000000 1364708549
EXT TRN CTL::
usn: 13
sp1:0x00000000 sp2:0x00000000 sp3:0x00000000 sp4:0x00000000
sp5:0x00000000 sp6:0x7fd900000000 sp7:0x00000000 sp8:0x7fd900000000
EXT TRN TBL::
index extflag extHash extPdbid/Spare1 extSpare2
-----------------------------------------------------------
0x00 0x00000000 0x00000000 0x00000001 0x00000000
0x01 0x00000000 0x00000000 0x00000001 0x00000000
0x02 0x00000000 0x00000000 0x00000001 0x00000000
0x03 0x00000000 0x00000000 0x00000001 0x00000000
0x04 0x00000000 0x00000000 0x00000001 0x00000000
0x05 0x00000000 0x00000000 0x00000001 0x00000000
0x06 0x00000000 0x00000000 0x00000001 0x00000000
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