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wwwhj8828com18088049999 ORACLE 如何检查找出损坏索引

hj8828 • 5 月前 • 124 次点击  

皇家国际开户教你:在Oracle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:

SQL> create tablespace test_data 2 datafile '/u01/app/oracle/oradata/gsp/test_data_01.dbf' 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/oracle/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 2 identified by 123456 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。

[oracle@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, Oracle 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

[oracle@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, Oracle. All rights reserved.

Connected to: Oracle 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/oracle/oradata/gsp/test_idx_01.dbf'

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>

因为一个段的第一个区的第一个块是FIRST LEVEL BITMAP BLOCK,第二个块是SECOND LEVEL BITMAP BLOCK,这两个块是用来管理free block的,第三个块是PAGETABLE SEGMENT HEADER,这个块才是segment里的HEADER_BLOCK,再后面的块就是用来记录数据的。关于这些知识,可以参考我博客ORACLE关于段的HEADER_BLOCK的一点浅析。而我们最上面的例子,是将第一个块构造为坏块,所以导致上面SQL无法查出。 我们重新构造案例,如我们将索引段的数据块构造为坏块,例如下面,将块号148人为构造坏块。那么此时这个脚本就能找出坏块索引了。所以综上述实验可以看出,这个脚本查找坏块索引是有条件的,要看索引段损坏的块是什么类型

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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