[20231026]bbed查看索引kd_off结构的问题.txt

[20231026]bbed查看索引kd_off结构的问题.txt --//使用bbed查看索引kd_off结构时存在问题，前面两项指向的偏移不对，从kd_off[2]算起，而且记录的是相对偏移=绝对偏移-kdxle偏移. --//遗漏的两项可以通过最大的kd_off项记录的地址+2 ,+4 获得. --//dump offset kd_off[max]+2 count 2 --//dump offset kd_off[max]+4 count 2 --//每次看最后两项比较麻烦，先给dump offset kd_off[max]+2 count 2，然后大小头颠倒, 计算出数字，在此基础上加上kdxle偏移， --//获得正确的偏移NNNN，然后再使用如下命令查询。 x /rxxx offset  NNNN --//自己尝试编写脚本实现正确的输出，并附带输出正确的x执行命令格式。主要自己很久不写bash shell脚本，拿来练习。 $ cat kd_off.sh #! /bin/bash # display bbed of kd_off structure and x command. # argument1=dba  argument2=bbed x format ff="/r"${2} a=$1 # get kd_off[max-2] and kdxle of address. kd_off_max=$(echo p dba $a kd_off | rlbbed | grep kd_off | sed -n '$p' |awk '{print substr($3,2)}') kdxle_offset=$(echo map dba $a | rlbbed | grep kdxle | awk '{print substr($5,2)}') kd_off_size=$(echo map dba $a| rlbbed | grep 'b2 kd_off' | sed -e 's/^.*\[//;s/].*$//' ) #echo kd_off_max=$kd_off_max kdxle_offset=$kdxle_offset  kd_off_size=$kd_off_size # get kd_off[max-1] and kd_off[max] of offset kd_off_offset=$(echo dump dba $a offset $((kd_off_max+2)) count 4 | rlbbed  | grep -A1 --  '----' | sed -n '$p' | tr -d ' \r') kd_off_offset=$(echo $kd_off_offset) kd_off_offset1=$(echo $kd_off_offset|awk '{print substr($a,3,2) substr($1,1,2)}') kd_off_offset2=$(echo $kd_off_offset|awk '{print substr($a,7,2) substr($1,5,2)}') #echo kd_off_offset=$kd_off_offset kd_off_offset1=$kd_off_offset1 kd_off_offset2=$kd_off_offset2 # display x command # echo p dba $a kd_off | rlbbed | grep kd_off | sed -n '3,$p' | awk '{print  $2}'| xargs -IQ echo x $ff dba $a '*'Q seq 2 $((kd_off_size-1)) | xargs -IQ echo x $ff dba $a '*'kd_off[Q] echo x $ff dba $a offset  $((0x${kd_off_offset1}+kdxle_offset)) echo x $ff dba $a offset  $((0x${kd_off_offset2}+kdxle_offset)) echo " " # display kd_off structure echo p dba $a kd_off | rlbbed | grep kd_off | sed -n '3,$p' | awk  -F'[][]' '{printf "%s[%d]%40s\n",$1,$2-2,$3}' printf "%s %s %34s %9s\n" b2 kd_off[$((kd_off_size-2))]  @$((kd_off_max+2))  $((0x$kd_off_offset1)) printf "%s %s %34s %9s\n" b2 kd_off[$((kd_off_size-1))]  @$((kd_off_max+4))  $((0x$kd_off_offset2)) --//验证测试看看: 1.环境: SCOTT@test01p> @ver1 PORT_STRING                    VERSION        BANNER                                                                               CON_ID ------------------------------ -------------- -------------------------------------------------------------------------------- ---------- IBMPC/WIN_NT64-9.1.0           12.2.0.1.0     Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production              0 2.测试: SCOTT@test01p> @ seg2 pk_emp SCOTT@test01p> @ pr ============================== SEG_MB                        : 0 SEG_OWNER                     : SCOTT SEG_SEGMENT_NAME              : PK_EMP SEG_PARTITION_NAME            : SEG_SEGMENT_TYPE              : INDEX SEG_TABLESPACE_NAME           : USERS BLOCKS                        : 8 HDRFIL                        : 11 HDRBLK                        : 154 PL/SQL procedure successfully completed. --//索引的root,叶子在dba=11,155. 使用bbed for windows无法识别数据文件os头,块偏移+1,输入11,156. BBED> p dba 11,156 kd_off b2 kd_off[0]                                @132      8036  --//8036+100(kdxle的偏移)=8136 表示索引数据的结尾，中间还                                                             --//保留8188-8136 = 52,不知道什么用处。 b2 kd_off[1]                                @134      0     --//kd_off[0],kd_off[1]执行的偏移不对，我估计oracle改变了                                                             --//kdxle结构，这4个字节的内容应该属于kdxle。而bbed版本没                                                             --//有维护跟上这种调整。 b2 kd_off[2]                                @136      8024 b2 kd_off[3]                                @138      8012 b2 kd_off[4]                                @140      8000 b2 kd_off[5]                                @142      7988 b2 kd_off[6]                                @144      7976 b2 kd_off[7]                                @146      7964 b2 kd_off[8]                                @148      7952 b2 kd_off[9]                                @150      7940 b2 kd_off[10]                               @152      7928 b2 kd_off[11]                               @154      7916 b2 kd_off[12]                               @156      7904 b2 kd_off[13]                               @158      7893 $ ./kd_off.sh  11,156 n x /rn dba 11,156 *kd_off[2] x /rn dba 11,156 *kd_off[3] x /rn dba 11,156 *kd_off[4] x /rn dba 11,156 *kd_off[5] x /rn dba 11,156 *kd_off[6] x /rn dba 11,156 *kd_off[7] x /rn dba 11,156 *kd_off[8] x /rn dba 11,156 *kd_off[9] x /rn dba 11,156 *kd_off[10] x /rn dba 11,156 *kd_off[11] x /rn dba 11,156 *kd_off[12] x /rn dba 11,156 *kd_off[13] x /rn dba 11,156 offset 7981 x /rn dba 11,156 offset 7969 b2 kd_off[0]                                @136      8024 b2 kd_off[1]                                @138      8012 b2 kd_off[2]                                @140      8000 b2 kd_off[3]                                @142      7988 b2 kd_off[4]                                @144      7976 b2 kd_off[5]                                @146      7964 b2 kd_off[6]                                @148      7952 b2 kd_off[7]                                @150      7940 b2 kd_off[8]                               @152      7928 b2 kd_off[9]                               @154      7916 b2 kd_off[10]                               @156      7904 b2 kd_off[11]                               @158      7893 b2 kd_off[12]                               @160      7881 b2 kd_off[13]                               @162      7869 --//注:前面显示的命令是x命令,后面的显示是正确的kd_off结构,意义不大!! BBED> x /rn dba 11,156 offset 7981 rowdata[16]                                 @7981 ----------- flag@7981:     0x00 (NONE) lock@7982:     0x02 keydata[6]:    0x02  0xc0  0x00  0x94  0x00  0x0c data key: col    0[3] @7990: 7902 BBED> x /rn dba 11,156 offset 7969 rowdata[4]                                  @7969 ---------- flag@7969:     0x00 (NONE) lock@7970:     0x02 keydata[6]:    0x02  0xc0  0x00  0x94  0x00  0x0d data key: col    0[3] @7978: 7934 SCOTT@test01p> select * from (select * from emp order by empno desc) where rownum<=2 ;      EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------       7934 MILLER     CLERK           7782 1982-01-23 00:00:00       1300                    10       7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20 --//完全能对上.