如何在Oracle数据库中找出损坏索引？

如何在***数据库中找出损坏索引？

在***数据库中如何找出损坏索引呢？ 下面我们人为构造一个案例，将索引块损坏。如下案例所示：

3 size 200M autoextend off

4 logging

5 segment space management auto

6 extent management local;

Tablespace created.

SQL> create tablespace test_index

2 datafile '/u01/app/***/oradata/gsp/test_idx_01.dbf'

3 size 200M autoextend off

4 logging

5 segment space management auto

6 extent management local;

Tablespace created.

SQL> create user kerry

3 default tablespace test_data;

User created.

SQL> grant connect to kerry;

SQL> grant resource to kerry;

上述脚本是创建表空间，创建用户kerry并授权，然后使用kerry账号登录数据库，构造测试数据，在TEST表上创建索引IX_TEST

SQL> show user;

USER is "KERRY"

SQL>

SQL> CREATE TABLE TEST(ID NUMBER(10), NAME VARCHAR2(64));

Table created.

SQL> DECLARE I NUMBER;

2 BEGIN

3 FOR I IN 1..1000 LOOP

4 INSERT INTO TEST VALUES(I, LPAD('T', 60));

5 END LOOP;

6 COMMIT;

7 END;

8 /

PL/SQL procedure successfully completed.

SQL> CREATE INDEX IX_TEST ON KERRY.TEST(NAME) TABLESPACE TEST_INDEX;

Index created.

然后使用下面脚本找到索引段数据库文件ID，以及索引段的第一个块的块号。

SQL> show user;

USER is "SYS"

SQL> col segment_name for a32;

SQL> col header_file for 9999;

SQL> col header_block for 9999;

SQL> select segment_name

2 ,header_file

3 ,header_block

4 ,blocks

5 from dba_segments ds

6 where ds.owner='KERRY' and ds.segment_name='IX_TEST';

SEGMENT_NAME HEADER_FILE HEADER_BLOCK BLOCKS

-------------------------------- ----------- ------------ ----------

IX_TEST 8 130 16

SQL>

构造坏块的方法有不少（例如BBED等），这里我们使用RMAN下面的命令clear,可以标记数据块为corrupt,标记数据文件8中130号数据块为坏块。

[***@DB-Server ~]$ rman target /

Recovery Manager: Release 11.2.0.1.0 - Production on Thu Sep 13 17:41:05 2018

Copyright (c) 1982, 2009, *** and/or its affiliates. All rights reserved.

connected to target database: GSP (DBID=644393201)

RMAN> recover datafile 8 block 130 clear;

Starting recover at 13-SEP-18

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=12 device type=DISK

Finished recover at 13-SEP-18

RMAN>

那么我们先来看看使用那些方法验证索引损坏了，测试验证一下看看是否可行。

1：使用ANALYZE分析验证索引结构

[***@DB-Server ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Thu Sep 13 17:42:03 2018

Copyright (c) 1982, 2009, ***. All rights reserved.

Connected to:

*** Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> analyze index kerry.ix_test validate structure;

analyze index kerry.ix_test validate structure

*

ERROR at line 1:

ORA-01578: ORACLE data block corrupted (file # 8, block # 130)

ORA-01110: data file 8: '/u01/app/***/oradata/gsp/test_idx_01.dbf'

如上截图所示，如果索引损坏（Corrupt Index），那么使用analyze index validate structure就会报错。要检查整个数据库所有的损坏索引（Corrupt Indexes）的话，就可以借助下面脚本：

spool analy_index.sql

SET PAGESIZE 50000;

SELECT

'ANALYZE INDEX ' || OWNER || '.' || INDEX_NAME|| ' VALIDATE STRUCTURE;' FROM DBA_INDEXES;

spool off;

@analy_index.sql

2：使用系统视图v$database_block_corruption查看损坏索引

如下所示，我们使用这个脚本来查看出现坏块的索引，发现这个脚本无法找出坏块索引。

set pagesize 50 linesize 170

col segment_name format a30

col partition_name format a30

SELECT DISTINCT file#,

segment_name,

segment_type,

tablespace_name,

partition_name

FROM dba_extents a,

v$database_block_corruption b

WHERE a.file_id = b.file#

AND a.block_id <= b.block#

AND a.block_id + a.blocks >= b.block#;

原因分析如下，视图v$database_block_corruption中有坏块记录，但是我们将索引段的第一个块标记为坏块后，在dba_extents中没有该索引段的记录了。所以这种情况下的索引损坏，这个SQL语句根本无法找出坏块索引。

SQL> SELECT file_id,

2 segment_name,

3 segment_type

4 FROM dba_extents

5 WHERE file_id = 8 ;

no rows selected

SQL> SELECT file_id,

2 segment_name,

3 segment_type

4 FROM dba_extents

5 WHERE owner = 'KERRY';

FILE_ID SEGMENT_NAME SEGMENT_TYPE

---------- -------------------------------- ------------------

7 TEST TABLE

7 TEST TABLE

SQL>

SQL> SELECT FILE_ID,

2 BLOCK_ID,

3 BLOCKS

FROM DBA_EXTENTS

4 5 WHERE OWNER ='&OWNER'

6 AND SEGMENT_NAME = '&TABLE_NAME';

Enter value for owner: KERRY

old 5: WHERE OWNER ='&OWNER'

new 5: WHERE OWNER ='KERRY'

Enter value for table_name: IX_TEST

old 6: AND SEGMENT_NAME = '&TABLE_NAME'

new 6: AND SEGMENT_NAME = 'IX_TEST'

FILE_ID BLOCK_ID BLOCKS

---------- ---------- ----------

8 144 8

8 152 8

SQL> SELECT HEADER_FILE

2 , HEADER_BLOCK

3 , BYTES

4 , BLOCKS

5 , EXTENTS

FROM DBA_SEGMENTS

6 7 WHERE OWNER='&OWNER' AND SEGMENT_NAME='&SEGMENT_NAME';

Enter value for owner: KERRY

Enter value for segment_name: IX_TEST

old 7: WHERE OWNER='&OWNER' AND SEGMENT_NAME='&SEGMENT_NAME'

new 7: WHERE OWNER='KERRY' AND SEGMENT_NAME='IX_TEST'

HEADER_FILE HEADER_BLOCK BYTES BLOCKS EXTENTS

----------- ------------ ---------- ---------- ----------

8 146 131072 16 2

SQL>

RMAN> recover datafile 8 block 148 clear;

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