[20190226]测试使用bbed恢复索引.txt

[20190226]测试使用bbed恢复索引.txt

--//上午做tab$删除恢复测试时发现,tab$的索引i_tab1很小.可以尝试使用bbed解决这个问题.
--//首先在普通表上做一个测试看看.

1.环境:
scott@book> @ ver1
port_string                    version        banner
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/linux 2.4.xx            11.2.0.4.0     oracle database 11g enterprise edition release 11.2.0.4.0 - 64bit production

scott@book> create table empy as select * from emp ;
table created.

scott@book> create index i_empy_empno on empy(empno);
index created.

scott@book> select rowid,empy.* from empy where rownum=1;
rowid                   empno ename      job              mgr hiredate                   sal       comm     deptno
------------------ ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
aaawpzaaeaaaailaaa       7369 smith      clerk           7902 1980-12-17 00:00:00        800                    20

scott@book> @ rowid aaawpzaaeaaaailaaa
    object       file      block        row rowid_dba            dba                  text
---------- ---------- ---------- ---------- -------------------- -------------------- ----------------------------------------
     91097          4        523          0  0x100020b           4,523                alter system dump datafile 4 block 523 ;

scott@book> select header_file,header_block,segment_name from dba_segments where owner=user and segment_name='i_empy_empno';
header_file header_block segment_name
----------- ------------ --------------------
          4          530 i_empy_empno
--//索引的roor节点在dba=4,531.

2.删除记录看看:

scott@book> delete from empy where empno not in (7369);
13 rows deleted.

scott@book> commit ;
commit complete.

--//仅仅保留1条.并且这条是empy表最小的empno号.

scott@book> alter system checkpoint ;
system altered.

3.先恢复表:
bbed> set dba 4,523
        dba             0x0100020b (16777739 4,523)


bbed> x /rnccntnnn *kdbr[0]
rowdata[529]                                @8150
------------
flag@8150: 0x2c (kdrhfl, kdrhff, kdrhfh)
lock@8151: 0x00
cols@8152:    8

col    0[3] @8153: 7369
col    1[5] @8157: smith
col    2[5] @8163: clerk
col    3[3] @8169: 7902
col    4[7] @8173: 1980-12-17 00:00:00
col    5[2] @8181: 800
col    6[0] @8184: *null*
col    7[2] @8185: 20
--//这条记录保留.

bbed> x /rnccntnnn *kdbr[1]
rowdata[486]                                @8107
------------
flag@8107: 0x3c (kdrhfl, kdrhff, kdrhfd, kdrhfh)
lock@8108: 0x02
cols@8109:    0

--//执行如下生成bbed脚本:
$ seq 1 13 | xargs -i{} echo 'x /rnccntnnn dba 4,523 *kdbr[{}]' | rlbbed | grep -b1 "^lock@" | grep "^flag@.*=0x3c" | cut -d: -f1| cut -d"@" -f2 | xargs -i{} echo assign dba 4,523 offset {}=0x2c
assign dba 4,523 offset 8107=0x2c
assign dba 4,523 offset 8064=0x2c
assign dba 4,523 offset 8023=0x2c
assign dba 4,523 offset 7978=0x2c
assign dba 4,523 offset 7937=0x2c
assign dba 4,523 offset 7896=0x2c
assign dba 4,523 offset 7856=0x2c
assign dba 4,523 offset 7818=0x2c
assign dba 4,523 offset 7775=0x2c
assign dba 4,523 offset 7737=0x2c
assign dba 4,523 offset 7699=0x2c
assign dba 4,523 offset 7660=0x2c
assign dba 4,523 offset 7621=0x2c

--//执行如上脚本,去除删除标识.

bbed> sum apply
check value for file 4, block 523:
current = 0x8c05, required = 0x8c05

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 523

block checking: dba = 16777739, block type = ktb-managed data block
data header at 0x7f6d56b9427c
kdbchk: the amount of space used is not equal to block size
        used=613 fsc=503 avsp=7451 dtl=8064
block 523 failed with check code 6110

--//dtl-used-fsc = avsp

bbed> p ktbbh.ktbbhitl[1]._ktbitun._ktbitfsc
sb2 _ktbitfsc                               @86       503

bbed> assign ktbbh.ktbbhitl[1]._ktbitun._ktbitfsc=0
sb2 _ktbitfsc                               @86       0

bbed> sum apply
check value for file 4, block 523:
current = 0x8df2, required = 0x8df2

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 523

block checking: dba = 16777739, block type = ktb-managed data block
data header at 0xe9427c
kdbchk: space available on commit is incorrect
        tosp=7980 fsc=0 stb=0 avsp=7451
block 523 failed with check code 6111

--//avsp+fsc+stb=tops.

bbed> assign kdbh.kdbhtosp=kdbh.kdbhavsp
sb2 kdbhtosp                                @136      7451

bbed> sum apply
check value for file 4, block 523:
current = 0x8fc5, required = 0x8fc5

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 523

--//ok, 现在对应块已经修复.

scott@book> alter system flush buffer_cache;
system altered.

scott@book> select * from empy ;
     empno ename      job              mgr hiredate                   sal       comm     deptno
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 smith      clerk           7902 1980-12-17 00:00:00        800                    20
      7499 allen      salesman        7698 1981-02-20 00:00:00       1600        300         30
      7521 ward       salesman        7698 1981-02-22 00:00:00       1250        500         30
      7566 jones      manager         7839 1981-04-02 00:00:00       2975                    20
      7654 martin     salesman        7698 1981-09-28 00:00:00       1250       1400         30
      7698 blake      manager         7839 1981-05-01 00:00:00       2850                    30
      7782 clark      manager         7839 1981-06-09 00:00:00       2450                    10
      7788 scott      analyst         7566 1987-04-19 00:00:00       3000                    20
      7839 king       president            1981-11-17 00:00:00       5000                    10
      7844 turner     salesman        7698 1981-09-08 00:00:00       1500          0         30
      7876 adams      clerk           7788 1987-05-23 00:00:00       1100                    20
      7900 james      clerk           7698 1981-12-03 00:00:00        950                    30
      7902 ford       analyst         7566 1981-12-03 00:00:00       3000                    20
      7934 miller     clerk           7782 1982-01-23 00:00:00       1300                    10
14 rows selected.

scott@book> select * from empy where empno in(7499,7369);
     empno ename      job              mgr hiredate                   sal       comm     deptno
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 smith      clerk           7902 1980-12-17 00:00:00        800                    20

--//可以发现走索引仅仅找到1条.

scott@book> analyze table empy validate structure cascade;
analyze table empy validate structure cascade
*
error at line 1:
ora-01499: table/index cross reference failure - see trace file
--//一般普通表的索引不用恢复,根据表重建就ok了.但是对于sys.tab$的索引不行,这也是做这个测试的原因.

4.恢复索引看看.
bbed> set dba 4,531
        dba             0x01000213 (16777747 4,531)

bbed> p kd_off
sb2 kd_off[0]                               @132      8032
sb2 kd_off[1]                               @134      0
sb2 kd_off[2]                               @136      8019
sb2 kd_off[3]                               @138      8006
sb2 kd_off[4]                               @140      7993
sb2 kd_off[5]                               @142      7980
sb2 kd_off[6]                               @144      7967
sb2 kd_off[7]                               @146      7954
sb2 kd_off[8]                               @148      7941
sb2 kd_off[9]                               @150      7928
sb2 kd_off[10]                              @152      7915
sb2 kd_off[11]                              @154      7902
sb2 kd_off[12]                              @156      7889
sb2 kd_off[13]                              @158      7877

--//可以发现bbed查看索引有问题,kd_off[0],kd_off[1]看到的偏移是不对的.实际上kd_off偏移从136开始kd_off[2].

bbed> x /rnx *kd_off[2]
rowdata[172]                                @8119
------------
flag@8119:     0x00 (none)
lock@8120:     0x00
data key:
col    0[3] @8122: 7369
col    1[6] @8126:  0x01  0x00  0x02  0x0b  0x00  0x00

--//这个表的第一条记录(最小值),我没有删除.empno=7369.

bbed> x /rnx *kd_off[3]
rowdata[159]                                @8106
------------
flag@8106:     0x01 (kdxrdel)
lock@8107:     0x02
data key:
col    0[3] @8109: 7499
col    1[6] @8113:  0x01  0x00  0x02  0x0b  0x00  0x01
--//对比删除与不删除的可以看出.flag不同,删除的flag=0x01.

$ seq 2 13 | xargs -i{} echo 'x /rnx dba 4,531 *kd_off[{}]' | rlbbed | grep -b1 "^lock@.*:*0x02$" | grep "flag@.*0x01" | cut -d: -f1 | cut -d@ -f2 |xargs -i{} echo assign dba 4,531 offset {}=0x00
assign dba 4,531 offset 8106=0x00
assign dba 4,531 offset 8093=0x00
assign dba 4,531 offset 8080=0x00
assign dba 4,531 offset 8067=0x00
assign dba 4,531 offset 8054=0x00
assign dba 4,531 offset 8041=0x00
assign dba 4,531 offset 8028=0x00
assign dba 4,531 offset 8015=0x00
assign dba 4,531 offset 8002=0x00
assign dba 4,531 offset 7989=0x00
assign dba 4,531 offset 7977=0x00
--//仅仅修改11条,还有2条需要修改标识.

bbed> dump  offset 160 count 4
 file: /mnt/ramdisk/book/users01.dbf (4)
 block: 531             offsets:  160 to  163   dba:0x01000213
---------------------------------------------------------------
 b81eab1e

 <64 bytes per line>

--// 说明: kd_off[13]的偏移量记录在偏移158,下面2条记录的偏移记录从160算起.
--// b81e 颠倒过来就是  1eb8=7864 , 记录相对偏移从kdxle算起(当前是100), 7864+100 = 7964
--// ab1e 颠倒过来就是  1eab=7851 , 记录相对偏移从kdxle算起(当前是100), 7851+100  = 7951

bbed> x /rnx offset 7964
rowdata[17]                                 @7964
-----------
flag@7964:     0x01 (kdxrdel)
lock@7965:     0x02
data key:
col    0[3] @7967: 7902
col    1[6] @7971:  0x01  0x00  0x02  0x0b  0x00  0x0c

bbed> x /rnx offset 7951
rowdata[4]                                  @7951
----------
flag@7951:     0x01 (kdxrdel)
lock@7952:     0x02
data key:
col    0[3] @7954: 7934
col    1[6] @7958:  0x01  0x00  0x02  0x0b  0x00  0x0d

--//也就是要补充执行如下:
assign dba 4,531 offset 7964=0x00
assign dba 4,531 offset 7951=0x00

--//执行如下脚本:
--//补充如果你仔细看就可以发现键值是按照行目录排序的.如果有记录插入,oracle是通过2分法定位插入行目录的位置,
--//你可以发现后面的偏移不是有序的,这也就是索引的块内无序,块间有序,但是如果索引分裂,oracle会重新排序.

assign dba 4,531 offset 8106=0x00
assign dba 4,531 offset 8093=0x00
assign dba 4,531 offset 8080=0x00
assign dba 4,531 offset 8067=0x00
assign dba 4,531 offset 8054=0x00
assign dba 4,531 offset 8041=0x00
assign dba 4,531 offset 8028=0x00
assign dba 4,531 offset 8015=0x00
assign dba 4,531 offset 8002=0x00
assign dba 4,531 offset 7989=0x00
assign dba 4,531 offset 7977=0x00
assign dba 4,531 offset 7964=0x00
assign dba 4,531 offset 7951=0x00

bbed> sum apply
check value for file 4, block 531:
current = 0x91b5, required = 0x91b5

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 531

block checking: dba = 16777747, block type = ktb-managed data block
**** actual free space = 7593 < kdxcoavs = 7787
**** actual rows marked deleted = 0 != kdxlende = 13
---- end index block validation
block 531 failed with check code 6401


bbed> p kdxle.kdxlende
sb2 kdxlende                                @118      13

bbed> assign  kdxle.kdxlende=0
sb2 kdxlende                                @118      0

bbed> sum apply
check value for file 4, block 531:
current = 0x91b8, required = 0x91b8

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 531

block checking: dba = 16777747, block type = ktb-managed data block
**** actual free space = 7593 < kdxcoavs = 7787
---- end index block validation
block 531 failed with check code 6401

bbed> p kdxle.kdxlexco.kdxcoavs
sb2 kdxcoavs                                @114      7787

bbed> assign kdxle.kdxlexco.kdxcoavs=7593
sb2 kdxcoavs                                @114      7593

bbed> sum apply
check value for file 4, block 531:
current = 0x927a, required = 0x927a

bbed> verify
dbverify - verification starting
file = /mnt/ramdisk/book/users01.dbf
block = 531

--//ok,现在完全修复了.

3.验证看看:
scott@book> alter system flush buffer_cache;
system altered.

scott@book> select * from empy where empno in(7499,7369);
     empno ename      job              mgr hiredate                   sal       comm     deptno
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 smith      clerk           7902 1980-12-17 00:00:00        800                    20
      7499 allen      salesman        7698 1981-02-20 00:00:00       1600        300         30

--//通过索引能定位行记录.
scott@book> analyze table empy validate structure cascade;
table analyzed.

--//analyze table empy validate structure cascade;一切ok,证明修复没有任何问题.

总结:
--//使用bbed修复索引有点繁琐,主要kd_off记录的偏移不对,从kd_off[2]算起.并且遗漏2条键值记录.

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