一、测试环境
sys@orcl> select file_name from dba_data_files;
FILE_NAME
---------------------------------------------
/u01/app/oracle/oradata/ORCL/system01.dbf
/u01/app/oracle/oradata/ORCL/sysaux01.dbf
/u01/app/oracle/oradata/ORCL/users01.dbf
/u01/app/oracle/oradata/ORCL/undotbs01.dbf
sys@orcl> create tablespace t1 datafile '/u01/app/oracle/oradata/ORCL/t1.dbf' size 10M autoextend off;
Tablespace created.
sys@orcl> create user cy identified by cy account unlock;
User created.
sys@orcl> grant dba to cy;
Grant succeeded.
sys@orcl> alter user cy default tablespace t1;
User altered.
sys@orcl> conn cy/cy
Connected.
cy@orcl> create table t1 as select * from scott.emp;
Table created.
cy@orcl> alter system checkpoint;
System altered.
cy@orcl> set linesize 1000
cy@orcl> select rowid,a.*,dbms_rowid.rowid_relative_fno(rowid) file#,dbms_rowid.rowid_block_number(rowid) block# from t1 a;
ROWID EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO FILE# BLOCK#
------------------ ---------- -------------------- ------------------ ---------- ------------------- ---------- ---------- ---------- ---------- ----------
AAASAsAAFAAAACDAAA 7369 SMITH CLERK 7902 1980-12-17 00:00:00 800 20 5 131
AAASAsAAFAAAACDAAB 7499 ALLEN SALESMAN 7698 1981-02-20 00:00:00 1600 300 30 5 131
AAASAsAAFAAAACDAAC 7521 WARD SALESMAN 7698 1981-02-22 00:00:00 1250 500 30 5 131
AAASAsAAFAAAACDAAD 7566 JONES MANAGER 7839 1981-04-02 00:00:00 2975 20 5 131
AAASAsAAFAAAACDAAE 7654 MARTIN SALESMAN 7698 1981-09-28 00:00:00 1250 1400 30 5 131
AAASAsAAFAAAACDAAF 7698 BLAKE MANAGER 7839 1981-05-01 00:00:00 2850 30 5 131
AAASAsAAFAAAACDAAG 7782 CLARK MANAGER 7839 1981-06-09 00:00:00 2450 10 5 131
AAASAsAAFAAAACDAAH 7788 SCOTT ANALYST 7566 1987-04-19 00:00:00 3000 20 5 131
AAASAsAAFAAAACDAAI 7839 KING PRESIDENT 1981-11-17 00:00:00 5000 10 5 131
AAASAsAAFAAAACDAAJ 7844 TURNER SALESMAN 7698 1981-09-08 00:00:00 1500 0 30 5 131
AAASAsAAFAAAACDAAK 7876 ADAMS CLERK 7788 1987-05-23 00:00:00 1100 20 5 131
AAASAsAAFAAAACDAAL 7900 JAMES CLERK 7698 1981-12-03 00:00:00 950 30 5 131
AAASAsAAFAAAACDAAM 7902 FORD ANALYST 7566 1981-12-03 00:00:00 3000 20 5 131
AAASAsAAFAAAACDAAN 7934 MILLER CLERK 7782 1982-01-23 00:00:00 1300 10 5 131
14 rows selected.
SELECT ROWID,
DBMS_ROWID.ROWID_OBJECT(ROWID) AS OBJECT,
DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) AS FILENUM,
DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) AS BLOCK,
DBMS_ROWID.ROWID_ROW_NUMBER(ROWID) AS ROWN
FROM T1;
cy@orcl> select object_id from dba_objects where object_name='T1';
OBJECT_ID
----------------------------
73772
说明：
rowid是指向块中特定行的指针，ROWID可用于提取转储特定块所需的文件和块号，对数据进行索引时，
索引块包含每行的行ID，以便更快地访问(执行计划中能看到)，当常规访问方法失败时，ROWID也可用于从块中提取数据
1.1 、rowid结构：
AAASAsAAFAAAACDAAN-->AAASAs(data object number) AAF(relative file number) AAAACD(block number ) AAN(row number)
32bit 10bit 22bit 16bit
说明：
数据库对象数量不能超过2^32
相对文件号不能超过2^10
单个数据文件可以管理的块数2^22
单个块行数不能超过2^16
cy@orcl> select rowid,dump(rowid,1016) from t1;
ROWID DUMP(ROWID,1016)
------------------ ----------------------------------------
AAASAsAAFAAAACDAAA Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,0 --> [00000000 000000001 00100000 00101100] [00000001 01][000000 00000000 10000011] [00000000 00000000]
73772 5 131 0
AAASAsAAFAAAACDAAB Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,1
AAASAsAAFAAAACDAAC Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,2
AAASAsAAFAAAACDAAD Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,3
AAASAsAAFAAAACDAAE Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,4
AAASAsAAFAAAACDAAF Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,5
AAASAsAAFAAAACDAAG Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,6
AAASAsAAFAAAACDAAH Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,7
AAASAsAAFAAAACDAAI Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,8
AAASAsAAFAAAACDAAJ Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,9
AAASAsAAFAAAACDAAK Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,a
AAASAsAAFAAAACDAAL Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,b
AAASAsAAFAAAACDAAM Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,c
AAASAsAAFAAAACDAAN Typ=69 Len=10: 0,1,20,2c,1,40,0,83,0,d
14 rows selected.
1.2、dump 数据块
方法一
cy@orcl> alter system dump datafile 5 block 131;
System altered.
cy@orcl> select * from v$diag_info;
INST_ID NAME
---------- --------------------------------------------------
VALUE
0
1 Default Trace File
/u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_84806.trc
0
12 rows selected.
cy@orcl> select file_id,file_name,bytes from dba_data_files;
FILE_ID FILE_NAME BYTES
1 /u01/app/oracle/oradata/ORCL/system01.dbf 4257218560
3 /u01/app/oracle/oradata/ORCL/sysaux01.dbf 671088640
4 /u01/app/oracle/oradata/ORCL/undotbs01.dbf 3795845120
7 /u01/app/oracle/oradata/ORCL/users01.dbf 5242880
5 /u01/app/oracle/oradata/ORCL/t1.dbf 10485760
方法2：
[oracle@19c01:/home/oracle/bbed]$dd if=/u01/app/oracle/oradata/ORCL/t1.dbf bs=8k skip=130 count=1 |od -xv >file.out
3+0 records in
3+0 records out
24576 bytes (25 kB) copied, 6.2261e-05 s, 395 MB/s
dd命令是从磁盘读取数据，所以dump前需要做一个checkpoint。
二、数据块结构
2.1、结构
BBED> set dba 5,131
DBA 0x01400083 (20971651 5,131)
BBED> map /v
File: /u01/app/oracle/oradata/ORCL/t1.dbf (5)
Block: 131 Dba:0x01400083
------------------------------------------------------------
KTB Data Block (Table/Cluster)
struct kcbh, 20 bytes @0
ub1 type_kcbh @0 --类型
ub1 frmt_kcbh @1
ub2 wrp2_kcbh @2
ub4 rdba_kcbh @4
ub4 bas_kcbh @8
ub2 wrp_kcbh @12
ub1 seq_kcbh @14
ub1 flg_kcbh @15
ub2 chkval_kcbh @16
ub2 spare3_kcbh @18
BBED> p kcbh
struct kcbh, 20 bytes @0
ub1 type_kcbh @0 0x06 --数据块
ub1 frmt_kcbh @1 0xa2 --in Oracle8, Oracle8i and Oracle9i this is 0x02
ub2 wrp2_kcbh @2 0x0000 --未使用
ub4 rdba_kcbh @4 0x01400083 --relative data block address -->01400083-->[0001010000][000000000010000011]-->131
ub4 bas_kcbh @8 0x02b73cbc --SCN base -->45563068
ub2 wrp_kcbh @12 0x0000 --SCN wrap
ub1 seq_kcbh @14 0x02 --seq#，对于同一个SCN，每次对数据块的改变而增加，这玩意就站1位，最大也就255
ub1 flg_kcbh @15 0x04 (KCBHFCKV) --flag 0x01 新数据块 0x02 延迟logging 0x04 check value 0x08 临时数据块
ub2 chkval_kcbh @16 0xc874 --块校验
ub2 spare3_kcbh @18 0x0000 --未使用
结构说明
type:
01：undo 段头
02：undo 数据块
03：保留的undo 头
04：保留的undo 数据块
05：数据段头 (temp，index，data 等等)
06：KTB managed data block (with ITL)
07: 临时表的数据块(没有 ITL)
08: sort key
09: sort run
10: 段自由列表
11: 数据文件头
flag：
#define KCBHFNEW 0x01 /* new block - zeroed data area */
#define KCBHFDLC 0x02 /* Delayed Logging Change advance SCN/seq */
#define KCBHFCKV 0x04 /* ChecK Value saved-block xor's to zero */
#define KCBHFTMP 0x08 /* Temporary block */
seq_kcbh:如果在同一SCN上有254个更改，则在块的下一个更改上强制新的SCN分配。255表示坏块
BBED> set offset 8
OFFSET 8
BBED> d
File: /u01/app/oracle/oradata/ORCL/t1.dbf (5)
Block: 131 Offsets: 8 to 519 Dba:0x01400083
------------------------------------------------------------------------
bc3cb702 00000204 74c80000 01000000 2c200100 ba3cb702 00800000 03003200
bas_kcbh：0x02b73cbc
0x02b73cbc + 0x06 + 0x02-->3cbc0602
2.2、块结构：
Start dump data blocks tsn: 6 file#:5 minblk 131 maxblk 131
Block dump from cache:
Dump of buffer cache at level 3 for pdb=0 tsn=6 rdba=20971651
BH (0x8e3e5f50) file#: 5 rdba: 0x01400083 (5/131) class: 1 ba: 0x8e1c8000
set: 6 pool: 3 bsz: 8192 bsi: 0 sflg: 2 pwc: 0,19
dbwrid: 0 obj: 73772 objn: 73772 tsn: [0/6] afn: 5 hint: f
hash: [0x8ffebfa0,0x6f207238] lru: [0x8e3e5ed0,0x8efeb060]
ckptq: [NULL] fileq: [NULL]
objq: [0x8efeb088,0x65181510] objaq: [0x8efeb098,0x65181500]
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' fscn: 0x2b73d04 tch: 1
flags: only_sequential_access
LRBA: [0x0.0.0] LSCN: [0x0] HSCN: [0x0] HSUB: [65535]
Printing buffer operation history (latest change first):
cnt: 6
buffer tsn: 6 rdba: 0x01400083 (5/131)
scn: 0x2b73cbc seq: 0x02 flg: 0x04 tail: 0x3cbc0602
frmt: 0x02 chkval: 0xc874 type: 0x06=trans data
说明
Rdba: 相对块地址 20971651(这是十进制) -->[000101][0000000000000010000011]--> 5 131
Scn: SCN号 0x2b73cbc(这是16进制) -->45563068
Seq: Sequence number:0x02 每次对数据块的改变而增加，这玩意就站1位，最大也就255，如果在同一SCN上有254个更改，则有必要在块的下一个更改上强制新的SCN分配。
SEQ -> 0 /* non-logged changes - do not advance seq# */
SEQ -> (UB1MAXVAL-1)/* maximum possible sequence number */ 2^8-1=254
SEQ -> (UB1MAXVAL) /* seq# to indicate a block is corrupt,equal to FF*/ 块错误，标记为255
Flg: Flag (defined in kcbh.h)
Tail: 一致性数据，用于验证块的开头和结尾是否一致相同版本（由SCNBase的低位两个字节加上块类型加上SCN序列号组成
Frmt: 8i以前是2，现在变a2
Chkval: DB_BLOCK_CHECKSUM = TRUE的时候用
Type: 块类型(data, index, kcb.h中定义) 偏移20，不是偏移0那个
3.3、块头：
Block header dump: 0x01400083
Object id on Block? Y
seg/obj: 0x1202c csc: 0x0000000002b73cba itc: 3 flg: E typ: 1 - DATA
brn: 0 bdba: 0x1400080 ver: 0x01 opc: 0
inc: 0 exflg: 0
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0xffff.000.00000000 0x00000000.0000.00 C--- 0 scn 0x0000000002b73cba
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
Seg/Obj: Seg/Obj ID 0x1202c-->73772 下文 偏移量24
Csc: 最后一次区块清理时的SCN 偏移28
Itc: itl槽数量 偏移36
Flg: 0 = on the freelist（空闲列表） E:指用的是ASSM(自动段空间管理)
Typ: 1 = DATA; 2 = INDEX
Fsl: ITL TX freelist slot
Fnx: 空闲列表下一个块，串一串
Itl: Interested transaction list index (ITLs determined by INITRANS and MAXTRANS)
Xid: 由und的段号+undo的槽号+undo槽号的覆盖次数三部分组成
Uba: Undo address (UndoDBA.SeqNo.RecordNo) undo块地址+seq+记录号
Flg: C = Committed; U = Commit Upper Bound; T = Active at CSC;B = Rollback of this UBA gives before image of the ITL.
Lck: 当前事务影响行数
Scn/Fsc: Scn = SCN of commited TX; Fsc = Free space credit (bytes)
BBED> p ktbbh
struct ktbbh, 96 bytes @20
ub1 ktbbhtyp @20 0x01 (KDDBTDATA)
union ktbbhsid, 4 bytes @24
ub4 ktbbhsg1 @24 0x0001202c
ub4 ktbbhod1 @24 0x0001202c
struct ktbbhcsc, 8 bytes @28
ub4 kscnbas @28 0x02b73cba
ub2 kscnwrp @32 0x8000
ub2 kscnwrp2 @34 0x0000
sb2 ktbbhict @36 3
ub1 ktbbhflg @38 0x32 (NONE)
ub1 ktbbhfsl @39 0x00
ub4 ktbbhfnx @40 0x01400080
struct ktbbhitl[0], 24 bytes @44
struct ktbitxid, 8 bytes @44
ub2 kxidusn @44 0xffff
ub2 kxidslt @46 0x0000
ub4 kxidsqn @48 0x00000000
struct ktbituba, 8 bytes @52
ub4 kubadba @52 0x00000000
ub2 kubaseq @56 0x0000
ub1 kubarec @58 0x00
ub2 ktbitflg @60 0x8000 (KTBFCOM)
union _ktbitun, 2 bytes @62
sb2 _ktbitfsc @62 -32768
ub2 _ktbitwrp @62 0x8000
ub4 ktbitbas @64 0x02b73cba
struct ktbbhitl[1], 24 bytes @68
struct ktbitxid, 8 bytes @68
ub2 kxidusn @68 0x0000
ub2 kxidslt @70 0x0000
ub4 kxidsqn @72 0x00000000
struct ktbituba, 8 bytes @76
ub4 kubadba @76 0x00000000
ub2 kubaseq @80 0x0000
ub1 kubarec @82 0x00
ub2 ktbitflg @84 0x0000 (NONE)
union _ktbitun, 2 bytes @86
sb2 _ktbitfsc @86 0
ub2 _ktbitwrp @86 0x0000
ub4 ktbitbas @88 0x00000000
struct ktbbhitl[2], 24 bytes @92
struct ktbitxid, 8 bytes @92
ub2 kxidusn @92 0x0000
ub2 kxidslt @94 0x0000
ub4 kxidsqn @96 0x00000000
struct ktbituba, 8 bytes @100
ub4 kubadba @100 0x00000000
ub2 kubaseq @104 0x0000
ub1 kubarec @106 0x00
ub2 ktbitflg @108 0x0000 (NONE)
union _ktbitun, 2 bytes @110
sb2 _ktbitfsc @110 0
ub2 _ktbitwrp @110 0x0000
ub4 ktbitbas @112 0x00000000
3.4、用户数据头
data_block_dump,data header at 0x8e1c807c
===============
tsiz: 0x1f80
hsiz: 0x2e
pbl: 0x8e1c807c
76543210
flag=--------
ntab=1
nrow=14
frre=-1
fsbo=0x2e
fseo=0x1d49
avsp=0x1d1b
tosp=0x1d1b
0xe:pti[0] nrow=14 offs=0
0x12:pri[0] offs=0x1f5a
0x14:pri[1] offs=0x1f2f
0x16:pri[2] offs=0x1f04
0x18:pri[3] offs=0x1edb
0x1a:pri[4] offs=0x1eae
0x1c:pri[5] offs=0x1e85
0x1e:pri[6] offs=0x1e5c
0x20:pri[7] offs=0x1e34
0x22:pri[8] offs=0x1e0e
0x24:pri[9] offs=0x1de3
0x26:pri[10] offs=0x1dbd
0x28:pri[11] offs=0x1d97
0x2a:pri[12] offs=0x1d70
0x2c:pri[13] offs=0x1d49
Tsiz: Total data area size 0x1f80-->8064不到8192
Hsiz: Data header size 0x2e -->46
Pbl: Pointer to buffer holding the block --这是说在内存的地址吧
Bdba: Block relative data block address (RDBA)
Flag: N = pctfree hit(clusters); F = do not put on free list; K = flushable cluster keys
Ntab: Number of tables (>1 in clusters)
Nrow: Number of ROWS
Frre: First free row index entry; -1 = you have to add one 第一个自由行索引条目
Fsbo: Free space begin offset 2e
Fseo: Free space end offset 1d49 这两句意思是说可以从偏移量1d49写到2e,倒着存你不能倒着说么
Avsp: Available space in the block 还有7451可以用
Tosp: Total available space when all TXs commit 事务槽空闲出来还能写多少
Nrow: Number of rows for first table
BBED> p kdbh
struct kdbh, 14 bytes @124
ub1 kdbhflag @124 0x00 (NONE)
sb1 kdbhntab @125 1
sb2 kdbhnrow @126 14
sb2 kdbhfrre @128 -1
sb2 kdbhfsbo @130 46
sb2 kdbhfseo @132 7497
sb2 kdbhavsp @134 7451
sb2 kdbhtosp @136 7451
3.5、数据行
block_row_dump:
tab 0, row 0, @0x1f5a -->8026
tl: 38 fb: --H-FL-- lb: 0x0 cc: 8
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 b5 02 16 01 01 01
col 5: [ 2] c2 09
col 6: *NULL*
col 7: [ 2] c1 15
tab 0, row 1, @0x1f2f -->7983
tl: 43 fb: --H-FL-- lb: 0x0 cc: 8
col 0: [ 3] c2 4b 64
col 1: [ 5] 41 4c 4c 45 4e
col 2: [ 8] 53 41 4c 45 53 4d 41 4e
col 3: [ 3] c2 4d 63
col 4: [ 7] 77 b5 02 14 01 01 01
col 5: [ 2] c2 11
col 6: [ 2] c2 04
col 7: [ 2] c1 1f
Tab: Table, row, offset
Lb: Lock byte: ITL entry that has this row locked
Cc: Number of columns in this ROW piece
Fb: Flag byte H = head of row piece; K = Cluster key; C = Cluster table member; D = Deleted row;F = First data piece; L = last data piece; P = First column continues from previous
piece; N = Last column continues in next piece
Tl: Row size (number of bytes plus data)
Col: Column data
BBED> p kdbr
sb2 kdbr[0] @142 8026
sb2 kdbr[1] @144 7983
sb2 kdbr[2] @146 7940
sb2 kdbr[3] @148 7899
sb2 kdbr[4] @150 7854
sb2 kdbr[5] @152 7813
sb2 kdbr[6] @154 7772
sb2 kdbr[7] @156 7732
sb2 kdbr[8] @158 7694
sb2 kdbr[9] @160 7651
sb2 kdbr[10] @162 7613
sb2 kdbr[11] @164 7575
sb2 kdbr[12] @166 7536
sb2 kdbr[13] @168 7497
BBED> p *kdbr[0]
rowdata[529]
------------
ub1 rowdata[529] @8150 0x2c
BBED> x /rnccntnnn
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: 1981-02-22 00:00:00
col 5[2] @8181: 800
col 6[0] @8184: *NULL*
col 7[2] @8185: 20
BBED> x /r
rowdata[529] @8150
------------
flag@8150: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8151: 0x00
cols@8152: 8
col 0[3] @8153: 0xc2 0x4a 0x46
col 1[5] @8157: 0x53 0x4d 0x49 0x54 0x48
col 2[5] @8163: 0x43 0x4c 0x45 0x52 0x4b
col 3[3] @8169: 0xc2 0x50 0x03
col 4[7] @8173: 0x77 0xb5 0x02 0x16 0x01 0x01 0x01
col 5[2] @8181: 0xc2 0x09
col 6[0] @8184: *NULL*
col 7[2] @8185: 0xc1 0x15
3.6、ASCII对照表
20 , 2c 8 38 D 44 P 50 \ 5c h 68 t 74
! 21 - 2d 9 39 E 45 Q 51 ] 5d i 69 u 75
" 22 . 2e : 3a F 46 R 52 ^ 5e j 6a v 76
# 23 / 2f ; 3b G 47 S 53 _ 5f k 6b w 77
$ 24 0 30 < 3c H 48 T 54 ` 60 l 6c x 78
% 25 1 31 = 3d I 49 U 55 a 61 m 6d y 79
& 26 2 32 > 3e J 4a V 56 b 62 n 6e z 7a
' 27 3 33 ? 3f K 4b W 57 c 63 o 6f { 7b
( 28 4 34 @ 40 L 4c X 58 d 64 p 70 | 7c
) 29 5 35 A 41 M 4d Y 59 e 65 q 71 } 7d
* 2a 6 36 B 42 N 4e Z 5a f 66 r 72 ~ 7e
+ 2b 7 37 C 43 O 4f [ 5b g 67 s 73 ^? 7f
三、关于块损坏
3.1、块检查
1、与硬盘做交互的时候需要做一致性检查，检查块版本、dba地址
2、一致性检查如下项：
- 块头SCNBase 和seq --bas_kcbh偏移量8，seq_kcbh偏移量14
- 块尾SCNBase和seq --tailchk 偏移量8188 由SCNBase的低位两个字节加上块类型加上SCN序列号组成
- 块类型 --偏移0就是
Tail: Consistency data used to verify that the beginning and the end of the block are
of the same version (Consists of lower order two bytes of SCNBase plus block Type plus SCN Seq number.)
SCNBase type seq
0x2b73cbc 0x06 0x02 --> 0x3cbc0602
案例：
ORA-600 (4519): Cache layer block type is incorrect
ORA-600 (4136): Check rollback segment block
ORA-600 (4154): Check rollback segment block
3.2、坏块类型：
介质坏块：从磁盘读取的无意义数据
软坏块：数据库系统检测到不一致后标记为坏块
seq的最大值为UB1MAXVAL-1（FF-1=255-1=254），因此当为FF就表示为软坏块。
3.3、ORA-1578
发现坏块的时候报出，报出的时候指出文件号和块号。
通常，ORA-1578错误是硬件问题造成的。如果ORA-1578错误总是返回相同的参数，则很可能是物理损坏的块。
如果参数每次都发生变化，则可能存在硬件问题，应检查内存和页面空间，并检查I/O子系统是否存在坏控制器。
获得十进制块号后，可以使用UNIX dd命令尝试从磁盘转储块。如果出现读取错误，这是硬件故障。此外，可以尝试转储该块几次，看看是否总能获得相同的数据。是对I/O子系统或坏控制器的检查。
3.4损坏的表中提取数据
(1) 使用可以跳过损坏块的特殊事件。这是迄今为止提取表数据的最简单的办法
(2) 使用 ROWID 范围扫描围绕损坏的块进行选择
(3) 有各种打捞程序/PLSQL 脚本
3.5、ORA-600
-
ORA-600[3374],[a],[b],[c],[d]
写磁盘的时候检查出错误，在内存损坏，检查dba,type,version和inc# -
ORA-600[kcbzpb_1],[d],[kind],[chk]
当块在内存中损坏时发出信号。唯一导致的原因是内存中的存储破坏了头部或尾部。- kcbzpb_1: 命名内部错误，引用源代码模块名称
- d : 块号
- kind : 损坏类型
- chk : 校验和标志
-
The ORA-600[3339] error comes with ORA-1578 and means either disk corruption or in-memory corruption after read.
3.6、如何处理：
检查alert日志和主机日志。使用诊断工具确定损坏类型。使用pacth查看什么问题。多检查几次确定是否依旧损坏。恢复数据。
始终尝试找出错误是否是永久性的。多次运行analyze命令，或者在可能的情况下执行关机和启动，然后重试以执行先前失败的操作。
找出是否还有更多的损坏。如果遇到一个，可能还有其他损坏的块。为此，使用DBVERIFY等工具。在尝试恢复数据之前，请执行块转储作为证据，以确定损坏的实际原因。使用UNIX dd和od-x对坏块进行十六进制转储。
考虑执行重做日志转储以检查对块所做的所有更改，以便您可以发现何时发生损坏。
注意：请记住，当遇到块损坏时，建议在验证硬件后执行介质恢复。
可能出现多种类型的硬件故障：
-
I/O硬件或固件错误
-
操作系统I/O或缓存问题
-
内存或分页问题
-
磁盘修复实用程序
3.7、DBVERIFY
只能检查数据文件，不能检查redo。检查块一致性。数据库运行时不应使用DBVERIFY，因为缓存中的块可能会重新损坏。
Block Checking: DBA = 29360495, Block Type = KTB-managed data block
data header at 0x7f8c98f4c064
kdbchk: the amount of space used is not equal to block size
used=613 fsc=41 avsp=7475 dtu=8129 dtl=8088 (s3=0, typ=6)
Page 367 failed with check code 6110
DBVERIFY - Verification complete
Total Pages Examined : 640
Total Pages Processed (Data) : 75
Total Pages Failing (Data) : 1
Total Pages Processed (Index): 17
Total Pages Failing (Index): 0
Total Pages Processed (Other): 479
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 69
Total Pages Marked Corrupt : 0
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 2275467 (0.2275467)
Influx：半一致状态，会重新检查，表示一开始检查head和tail不一致，后面一致。因为dbwr正在处理。如果还不一致则是坏块。
DBVERIFY仅检查逻辑损坏；也就是说，它使用kcb.h仅检查header/footer信息。因此，在高水位线以上可能发生损坏。
3.8、Analyze命令
- 做逻辑块检查
- 不标记软损坏，只是报告
- 表示里面有数据或索引
- 对于分区表，Oracle服务器还验证该行是否属于正确的分区。如果行未正确排序，则将rowid插入到invalid_rows表中。
SQL> analyze table xxx validate structure cascade;
SQL> analyze index xxx validate structure;
SQL> analyze cluster xxx validate structure;
SQL> analyze table xxx partition (p1) validate structure into invalid_rows;
一个简单的select语句（select*from
