[20181226]简单探究cluster table.txt

2019-01-02 14:15:49来源:cnblogs.com作者:lfree人点击

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[20181226]简单探究cluster table.txt

--//简单探究cluster table.以前也做过,有点生疏了.

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

2.建立测试环境:
create cluster deptx_cluster (deptno number(2));

create table deptx
(
  deptno  number(2) ,
  dname   varchar2(14 byte),
  loc     varchar2(13 byte)
) cluster deptx_cluster (deptno);

alter table deptx add constraint pk_deptx primary key (deptno);  

create table empx
(
  empno     number(4) ,
  ename     varchar2(10 byte),
  job       varchar2(9 byte),
  mgr       number(4),
  hiredate  date,
  sal       number(7,2),
  comm      number(7,2),
  deptno    number(2) references deptx
) cluster deptx_cluster (deptno);

alter table empx  add constraint constraint_name primary key (empno);  

create index i_deptx_cluster_deptno on cluster deptx_cluster;
--//注这里不能使用unique,否则报ORA-01715: UNIQUE may not be used with a cluster index

insert into deptx select * from dept where deptno=10;
insert into empx select * from emp where deptno=10;

insert into deptx select * from dept where deptno=20;
insert into empx select * from emp where deptno=20;

insert into deptx select * from dept where deptno=30;
insert into empx select * from emp where deptno=30;

insert into deptx select * from dept where deptno=40;
insert into empx select * from emp where deptno=40;

commit;

3.查看数据:
SCOTT@book> select rowid,deptx.* from deptx;
ROWID                  DEPTNO DNAME          LOC
------------------ ---------- -------------- -------------
AAAWEfAAEAAAAIrAAA         20 RESEARCH       DALLAS
~~~~~~~~~~~~~~~~~~
AAAWEfAAEAAAAItAAA         30 SALES          CHICAGO
AAAWEfAAEAAAAIuAAA         40 OPERATIONS     BOSTON
AAAWEfAAEAAAAIvAAA         10 ACCOUNTING     NEW YORK

SCOTT@book> select rowid,empx.* from empx where deptno=20;
ROWID                   EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
------------------ ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
AAAWEfAAEAAAAIrAAA       7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20
~~~~~~~~~~~~~~~~~~
AAAWEfAAEAAAAIrAAB       7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20
AAAWEfAAEAAAAIrAAC       7788 SCOTT      ANALYST         7566 1987-04-19 00:00:00       3000                    20
AAAWEfAAEAAAAIrAAD       7876 ADAMS      CLERK           7788 1987-05-23 00:00:00       1100                    20
AAAWEfAAEAAAAIrAAE       7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20

SCOTT@book> @ dpc '' ''
PLAN_TABLE_OUTPUT
-------------------------------------
SQL_ID  fw7tmp1r74rf4, child number 0
-------------------------------------
select rowid,empx.* from empx where deptno=20
Plan hash value: 1833007843
------------------------------------------------------------------------------------------------
| Id  | Operation            | Name                   | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT     |                        |        |       |     2 (100)|          |
|   1 |  TABLE ACCESS CLUSTER| EMPX                   |      5 |   190 |     2   (0)| 00:00:01 |
|*  2 |   INDEX UNIQUE SCAN  | I_DEPTX_CLUSTER_DEPTNO |      1 |       |     1   (0)| 00:00:01 |
------------------------------------------------------------------------------------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
   1 - SEL$1 / EMPX@SEL$1
   2 - SEL$1 / EMPX@SEL$1
Predicate Information (identified by operation id):
---------------------------------------------------
   2 - access("DEPTNO"=20)

--//可以发现查询empx表的deptno=20可以利用cluster table的索引.另外你可以注意一个特点cluster table里面的表rowid可以相同.比如下划线的内容.
--//实际上这样设计相关表的查询都保存在相同块中,连接访问会快许多.

SCOTT@book> @ rowid AAAWEfAAEAAAAIrAAA
    OBJECT       FILE      BLOCK        ROW ROWID_DBA            DBA                  TEXT
---------- ---------- ---------- ---------- -------------------- -------------------- ----------------------------------------
     90399          4        555          0  0x100022B           4,555                alter system dump datafile 4 block 555 ;
--//转储dba=4,555看看.

3.转储分析:
SCOTT@book> alter system flush buffer_cache;
System altered.

SCOTT@book> alter system dump datafile 4 block 555 ;
System altered.

Block header dump:  0x0100022b
 Object id on Block? Y
 seg/obj: 0x1611f  csc: 0x03.175f42b6  itc: 2  flg: E  typ: 1 - DATA
     brn: 0  bdba: 0x1000228 ver: 0x01 opc: 0
     inc: 0  exflg: 0

 Itl           Xid                  Uba         Flag  Lck        Scn/Fsc
0x01   0x0009.01b.00000a44  0x00c00356.0394.31  C---    0  scn 0x0003.175f42b6
0x02   0x000a.001.00004cfa  0x00c02e94.0ef9.27  --U-    6  fsc 0x0000.175f42cc
bdba: 0x0100022b
data_block_dump,data header at 0x7f286b5f1064
===============
tsiz: 0x1f98
hsiz: 0x28
pbl: 0x7f286b5f1064
     76543210
flag=-------K
ntab=3
nrow=7
frre=-1
fsbo=0x28
fseo=0x1eb9
avsp=0x1e91
tosp=0x1e91
0xe:pti[0]  nrow=1  offs=0
0x12:pti[1] nrow=1  offs=1
0x16:pti[2] nrow=5  offs=2
--//说明有3个表,cluster表deptx_cluster以及表deptx,empx.行数分别是1,1,5(下面可以看到对于7条记录).后面offs表示偏移量.
0x1a:pri[0] offs=0x1f82
0x1c:pri[1] offs=0x1f6e
0x1e:pri[2] offs=0x1f4b
0x20:pri[3] offs=0x1f25
0x22:pri[4] offs=0x1f00
0x24:pri[5] offs=0x1edd
0x26:pri[6] offs=0x1eb9
block_row_dump:
tab 0, row 0, @0x1f82                               --//表0 cluster table deptx_cluster
tl: 22 fb: K-H-FL-- lb: 0x0  cc: 1
--//fb: K-H-FL--, K meaning cluster key.
--//The remaining rows have the second high order bit set (fb: -CH-FL--),
--//C meaning cluster table member.
curc: 6 comc: 6 pk: 0x0100022b.0 nk: 0x0100022b.0
--//curc: 6 Current row count for this key in this block
--//comc: 6 Committed row count for this key in this block
--//pk: pk: 0x0100022b.0 ROWID of Previous block for this cluster key
--//nk: 0x0100022b.0 ROWID of Next block for this cluster key
col  0: [ 2]  c1 15                                 --//数字20.
tab 1, row 0, @0x1f6e
tl: 20 fb: -CH-FL-- lb: 0x2  cc: 2 cki: 0           --//表1 deptx
                                                    --//C meaning cluster table member.
col  0: [ 8]  52 45 53 45 41 52 43 48               --//对应内容'RESEARCH'
col  1: [ 6]  44 41 4c 4c 41 53                     --//对应内容'DALLAS'
tab 2, row 0, @0x1f4b                               --//表2 empx
tl: 35 fb: -CH-FL-- lb: 0x2  cc: 6 cki: 0
col  0: [ 3]  c2 4a 46
col  1: [ 5]  53 4d 49 54 48
col  2: [ 5]  43 4c 45 52 4b
col  3: [ 3]  c2 50 03
col  4: [ 7]  77 b4 0c 11 01 01 01
col  5: [ 2]  c2 09
tab 2, row 1, @0x1f25
tl: 38 fb: -CH-FL-- lb: 0x2  cc: 6 cki: 0
col  0: [ 3]  c2 4c 43
col  1: [ 5]  4a 4f 4e 45 53
col  2: [ 7]  4d 41 4e 41 47 45 52
col  3: [ 3]  c2 4f 28
col  4: [ 7]  77 b5 04 02 01 01 01
col  5: [ 3]  c2 1e 4c
tab 2, row 2, @0x1f00
tl: 37 fb: -CH-FL-- lb: 0x2  cc: 6 cki: 0
col  0: [ 3]  c2 4e 59
col  1: [ 5]  53 43 4f 54 54
col  2: [ 7]  41 4e 41 4c 59 53 54
col  3: [ 3]  c2 4c 43
col  4: [ 7]  77 bb 04 13 01 01 01
col  5: [ 2]  c2 1f
tab 2, row 3, @0x1edd
tl: 35 fb: -CH-FL-- lb: 0x2  cc: 6 cki: 0
col  0: [ 3]  c2 4f 4d
col  1: [ 5]  41 44 41 4d 53
col  2: [ 5]  43 4c 45 52 4b
col  3: [ 3]  c2 4e 59
col  4: [ 7]  77 bb 05 17 01 01 01
col  5: [ 2]  c2 0c
tab 2, row 4, @0x1eb9
tl: 36 fb: -CH-FL-- lb: 0x2  cc: 6 cki: 0
col  0: [ 3]  c2 50 03
col  1: [ 4]  46 4f 52 44
col  2: [ 7]  41 4e 41 4c 59 53 54
col  3: [ 3]  c2 4c 43
col  4: [ 7]  77 b5 0c 03 01 01 01
col  5: [ 2]  c2 1f
end_of_block_dump
End dump data blocks tsn: 4 file#: 4 minblk 555 maxblk 555

--//通过bbed观察:
BBED> p dba 4,555 kdbt
struct kdbt[0], 4 bytes                     @114
   sb2 kdbtoffs                             @114      0
   sb2 kdbtnrow                             @116      1
struct kdbt[1], 4 bytes                     @118
   sb2 kdbtoffs                             @118      1
   sb2 kdbtnrow                             @120      1
struct kdbt[2], 4 bytes                     @122
   sb2 kdbtoffs                             @122      2
   sb2 kdbtnrow                             @124      5

--//与如下对应:
0xe:pti[0]  nrow=1  offs=0
0x12:pti[1] nrow=1  offs=1
0x16:pti[2] nrow=5  offs=2

--//比如可以看出对于当前块表empx位于*kdbr[2]开始.

BBED> x /rn *kdbr[0]
rowdata[201]                                @8166
------------
flag@8166: 0xac (KDRHFL, KDRHFF, KDRHFH, KDRHFK)       --//cluster key.行头为ac 普通表为2c
lock@8167: 0x00
cols@8168:    1
kref@8169:    6
mref@8171:    6
hrid@8173:0x0100022b.0
nrid@8179:0x0100022b.0
col    0[2] @8185: 20

BBED> x /rcc *kdbr[1]
rowdata[181]                                @8146
------------
flag@8146: 0x6c (KDRHFL, KDRHFF, KDRHFH, KDRHFC)      --//cluser table member .行头为6c 删除为7c,实际上加入KDRHFD标志.
lock@8147: 0x02
cols@8148:    2
col    0[8] @8150: RESEARCH
col    1[6] @8159: DALLAS
--//注:不包括cluster table key.

BBED> x /rnccntnnn *kdbr[2]
rowdata[146]                                @8111
------------
flag@8111: 0x6c (KDRHFL, KDRHFF, KDRHFH, KDRHFC)
lock@8112: 0x02
cols@8113:    6
col    0[3] @8115: 7369
col    1[5] @8119: SMITH
col    2[5] @8125: CLERK
col    3[3] @8131: 7902
col    4[7] @8135: 1980-12-17 00:00:00
col    5[2] @8143: 800

4.做一个删除的手工恢复看看.

SCOTT@book> delete from empx where empno=7566;
1 row deleted.

SCOTT@book> commit ;
Commit complete.

SCOTT@book> alter system flush buffer_cache;
System altered.

SCOTT@book> alter system dump datafile 4 block 555 ;
System altered.

--//仅仅贴出改动部分:
block_row_dump:
tab 0, row 0, @0x1f82
tl: 22 fb: K-H-FL-- lb: 0x0  cc: 1
curc: 6 comc: 5 pk: 0x0100022b.0 nk: 0x0100022b.0
col  0: [ 2]  c1 15
--//comc 5 少1条记录.

...

tl: 35 fb: -CH-FL-- lb: 0x0  cc: 6 cki: 0
col  0: [ 3]  c2 4a 46
col  1: [ 5]  53 4d 49 54 48
col  2: [ 5]  43 4c 45 52 4b
col  3: [ 3]  c2 50 03
col  4: [ 7]  77 b4 0c 11 01 01 01
col  5: [ 2]  c2 09
tab 2, row 1, @0x1f25
tl: 4 fb: -CHDFL-- lb: 0x2  cc: 0 cki: 0  --//加入D标志.
tab 2, row 2, @0x1f00

--//如果手工修复,需要修改2处.

BBED> x /rn *kdbr[0]
rowdata[201]                                @8166
------------
flag@8166: 0xac (KDRHFL, KDRHFF, KDRHFH, KDRHFK)
lock@8167: 0x00
cols@8168:    1
kref@8169:    6
mref@8171:    5
~~~~~~~~~~~~~~~
hrid@8173:0x0100022b.0
nrid@8179:0x0100022b.0
col    0[2] @8185: 20

BBED> x /rnccntnnn *kdbr[3]
rowdata[108]                                @8073
------------
flag@8073: 0x7c (KDRHFL, KDRHFF, KDRHFD, KDRHFH, KDRHFC)
lock@8074: 0x02
cols@8075:    0

--//执行如下:
assign /d offset 8171=6;
assign /x offset 8073=6c;

BBED> assign /d offset 8171=6;
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
ub1 rowdata[0]                              @8171     0x06

BBED> assign /x offset 8073=6c;
ub1 rowdata[0]                              @8073     0x6c

--//检查:
BBED> x /rn *kdbr[0]
rowdata[201]                                @8166
------------
flag@8166: 0xac (KDRHFL, KDRHFF, KDRHFH, KDRHFK)
lock@8167: 0x00
cols@8168:    1
kref@8169:    6
mref@8171:    6
hrid@8173:0x0100022b.0
nrid@8179:0x0100022b.0
col    0[2] @8185: 20

BBED> x /rnccntnnn *kdbr[2]
rowdata[146]                                @8111
------------
flag@8111: 0x6c (KDRHFL, KDRHFF, KDRHFH, KDRHFC)
lock@8112: 0x00
cols@8113:    6

col    0[3] @8115: 7369
col    1[5] @8119: SMITH
col    2[5] @8125: CLERK
col    3[3] @8131: 7902
col    4[7] @8135: 1980-12-17 00:00:00
col    5[2] @8143: 800

BBED> sum apply
Check value for File 4, Block 555:
current = 0xf209, required = 0xf209

BBED> verify
DBVERIFY - Verification starting
FILE = /mnt/ramdisk/book/users01.dbf
BLOCK = 555

Block Checking: DBA = 16777771, Block Type = KTB-managed data block
data header at 0x7fd6f1fd9264
kdbchk: the amount of space used is not equal to block size
        used=263 fsc=34 avsp=7825 dtl=8088
Block 555 failed with check code 6110
--//空间问题暂时不理会.
--//验证修改是否有效.
SCOTT@book> select rowid,empx.* from empx where deptno=20;
ROWID                   EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
------------------ ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
AAAWEfAAEAAAAIrAAA       7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20
AAAWEfAAEAAAAIrAAB       7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20
AAAWEfAAEAAAAIrAAC       7788 SCOTT      ANALYST         7566 1987-04-19 00:00:00       3000                    20
AAAWEfAAEAAAAIrAAD       7876 ADAMS      CLERK           7788 1987-05-23 00:00:00       1100                    20
AAAWEfAAEAAAAIrAAE       7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20
--//empno=7566可以查询到.如果通过索引是无法查询到信息.
SCOTT@book> select rowid,empx.* from empx where empno=7566;
no rows selected

--//如果不修复comc的偏移,还原:
BBED> assign /d offset 8171=5;
ub1 rowdata[0]                              @8171     0x05

BBED> sum apply
Check value for File 4, Block 555:
current = 0xf109, required = 0xf109

BBED> verify
DBVERIFY - Verification starting
FILE = /mnt/ramdisk/book/users01.dbf
BLOCK = 555

Block Checking: DBA = 16777771, Block Type = KTB-managed data block
data header at 0x105cc64
kdbchk:  key comref count wrong
         keyslot=0
Block 555 failed with check code 6121

--//会报如上错误.不过查询没有问题.

SCOTT@book> alter system flush buffer_cache;
System altered.

SCOTT@book> select rowid,empx.* from empx where deptno=20;
ROWID                   EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
------------------ ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
AAAWEfAAEAAAAIrAAA       7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20
AAAWEfAAEAAAAIrAAB       7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20
AAAWEfAAEAAAAIrAAC       7788 SCOTT      ANALYST         7566 1987-04-19 00:00:00       3000                    20
AAAWEfAAEAAAAIrAAD       7876 ADAMS      CLERK           7788 1987-05-23 00:00:00       1100                    20
AAAWEfAAEAAAAIrAAE       7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20

5.最后修复bbed verify的错误.
--//这个错误我建议不熟悉bbed,不再修复,比较繁琐.

BBED> assign /d offset 8171=6;
ub1 rowdata[0]                              @8171     0x06

BBED> sum apply
Check value for File 4, Block 555:
current = 0xf209, required = 0xf209

BBED> verify
DBVERIFY - Verification starting
FILE = /mnt/ramdisk/book/users01.dbf
BLOCK = 555

Block Checking: DBA = 16777771, Block Type = KTB-managed data block
data header at 0x105cc64
kdbchk: the amount of space used is not equal to block size
        used=263 fsc=34 avsp=7825 dtl=8088
Block 555 failed with check code 6110

--//理论used+fsc+avsp=dtl
--//dtl-used-fsc= 8088-263-34 = 7791
--//然后assign kdbh.kdbhavsp=7791,如果修改事务itl槽信息,步骤也不少.

BBED> assign kdbh.kdbhavsp=7791
sb2 kdbhavsp                                @110      7791

BBED> sum apply
Check value for File 4, Block 555:
current = 0xf2f7, required = 0xf2f7

BBED> verify
DBVERIFY - Verification starting
FILE = /mnt/ramdisk/book/users01.dbf
BLOCK = 555

Block Checking: DBA = 16777771, Block Type = KTB-managed data block
data header at 0x107ec64
kdbchk: space available on commit is incorrect
        tosp=7863 fsc=34 stb=0 avsp=7791
Block 555 failed with check code 6111

--//tosp - fsc - stb = avsp.
--//avsp+fsstb=  7791+34+0 = 7825.

BBED> assign kdbh.kdbhtosp=7825
sb2 kdbhtosp                                @112      7825

BBED> sum apply
Check value for File 4, Block 555:
current = 0xf2d1, required = 0xf2d1

BBED> verify
DBVERIFY - Verification starting
FILE = /mnt/ramdisk/book/users01.dbf
BLOCK = 555
DBVERIFY - Verification complete
Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 0
Total Blocks Influx           : 0
Message 531 not found;  product=RDBMS; facility=BBED

6.修复索引:
SCOTT@book> alter index pk_empx rebuild online;
Index altered.
--//注意一定要加online,不然不回表,无法修复错误索引错误.

SCOTT@book> select rowid,empx.* from empx where empno=7566;
ROWID                   EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
------------------ ---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
AAAWEfAAEAAAAIrAAB       7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20

总结:
--//修复cluster table要比普通表有难度.


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