Database Corruptions - Physical & Logical Corruptions

Database Corruptions - Physical & Logical Corruptions

--logical corruptions (table level):

SQL> ANALYZE TABLE scott.emp VALIDATE STRUCTURE;

--physical and logical corruptions through RMAN:

RMAN> validate database;

--logical corruptions inside the database:

RMAN> BACKUP VALIDATE CHECK LOGICAL DATABASE ARCHIVELOG ALL;

--logical corruption for datafile

RMAN> validate datafile 4; (block level)

--physical corruptions at os level

[oracle@OEL-11g ~]$ dbv

DBVERIFY: Release 11.2.0.3.0 - Production on Thu Oct 8 09:33:10 2015

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Keyword     Description                    (Default)
----------------------------------------------------
FILE        File to Verify                 (NONE)
START       Start Block                    (First Block of File)
END         End Block                      (Last Block of File)
BLOCKSIZE   Logical Block Size             (8192)
LOGFILE     Output Log                     (NONE)
FEEDBACK    Display Progress               (0)
PARFILE     Parameter File                 (NONE)
USERID      Username/Password              (NONE)
SEGMENT_ID  Segment ID (tsn.relfile.block) (NONE)
HIGH_SCN    Highest Block SCN To Verify    (NONE)
            (scn_wrap.scn_base OR scn)         
[oracle@OEL-11g ~]$ dbv file=/oradata/ORADB/users01.dbf

DBVERIFY: Release 11.2.0.3.0 - Production on Thu Oct 8 09:33:32 2015
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
DBVERIFY - Verification starting : FILE = /oradata/ORADB/users01.dbf
DBVERIFY - Verification complete

Total Pages Examined         : 640
Total Pages Processed (Data) : 14
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 13
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 596
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 17
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 1022004 (0.1022004)

RMAN provides a data recovery advisory tool logical and physical corruptions:

RMAN> list failure;
RMAN> advise failure;
RMAN> repair failure;

RMAN> list failure;

List of Database Failures
=========================

Failure ID Priority Status    Time Detected Summary
---------- -------- --------- ------------- -------
502        HIGH     OPEN      08-OCT-15     One or more non-system datafiles are corrupt

RMAN>

RMAN> advise failure;

List of Database Failures
=========================

Failure ID Priority Status    Time Detected Summary
---------- -------- --------- ------------- -------
502        HIGH     OPEN      08-OCT-15 

One or more non-system datafiles are corrupt analyzing automatic repair options; this may take some time using channel ORA_DISK_1
analyzing automatic repair options complete

Mandatory Manual Actions
========================
no manual actions available

Optional Manual Actions
=======================
no manual actions available

Automated Repair Options
========================
Option Repair Description
------ ------------------
1      Restore and recover datafile 4
  Strategy: The repair includes complete media recovery with no data loss
  Repair script: /oracle/base/diag/rdbms/oradb/ORADB/hm/reco_1379785849.hm

RMAN> repair failure;

Strategy: The repair includes complete media recovery with no data loss
Repair script: /oracle/base/diag/rdbms/oradb/ORADB/hm/reco_1379785849.hm

contents of repair script:
   # restore and recover datafile
   sql 'alter database datafile 4 offline';
   restore datafile 4;
   recover datafile 4;
   sql 'alter database datafile 4 online';

Do you really want to execute the above repair (enter YES or NO)? yes
executing repair script

sql statement: alter database datafile 4 offline

Starting restore at 08-OCT-15
using channel ORA_DISK_1

channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00004 to /oradata/ORADB/users01.dbf
channel ORA_DISK_1: reading from backup piece /oradata/fra/ORADB/backupset/2015_10_07/o1_mf_nnnd0_TAG20151007T093119_c1968k0o_.bkp
channel ORA_DISK_1: piece handle=/oradata/fra/ORADB/backupset/2015_10_07/o1_mf_nnnd0_TAG20151007T093119_c1968k0o_.bkp tag=TAG20151007T093119
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 08-OCT-15

Starting recover at 08-OCT-15
using channel ORA_DISK_1

starting media recovery

archived log for thread 1 with sequence 4 is already on disk as file /oradata/fra/arch/1_4_892373901.dbf
archived log for thread 1 with sequence 5 is already on disk as file /oradata/fra/arch/1_5_892373901.dbf
channel ORA_DISK_1: starting archived log restore to default destination
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=3
channel ORA_DISK_1: reading from backup piece /oradata/fra/ORADB/backupset/2015_10_07/o1_mf_annnn_TAG20151007T093251_c196ccmm_.bkp
channel ORA_DISK_1: piece handle=/oradata/fra/ORADB/backupset/2015_10_07/o1_mf_annnn_TAG20151007T093251_c196ccmm_.bkp tag=TAG20151007T093251
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
archived log file name=/oradata/fra/arch/1_3_892373901.dbf thread=1 sequence=3
media recovery complete, elapsed time: 00:00:01
Finished recover at 08-OCT-15

sql statement: alter database datafile 4 online
repair failure complete

Query to check corruptions:


SQL> SELECT DISTINCT owner, segment_name FROM  v$database_block_corruption dbc JOIN dba_extents e ON dbc.file# = e.file_id AND dbc.block# BETWEEN e.block_id and e.block_id+e.blocks-1 ORDER BY 1,2;