allaboutoracleblockcorruption(一)

2014-11-24 17:00:04 · 作者: · 浏览: 0

ORA-01578错误是Oracle中常见的物理坏块讹误(Corruption)错误,从10g以后在拥有完整备份和归档日志的情况下可以通过blockrecover/recover命令在线恢复该坏块,前提是数据块所在磁道在物理上仍可用。

以下是一个在没有充分备份情况下的ORA-01578错误的解决,前提是能够容忍坏块所在数据的丢失:

SQL> exec DBMS_STATS.GATHER_DATABASE_STATS;
BEGIN DBMS_STATS.GATHER_DATABASE_STATS; END;

*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 870212)
ORA-01110: data file 4:
'/s01/oradata/G10R25/datafile/o1_mf_users_7ch7d4nx_.dbf'
ORA-06512: at "SYS.DBMS_STATS", line 15188
ORA-06512: at "SYS.DBMS_STATS", line 15530
ORA-06512: at "SYS.DBMS_STATS", line 15674
ORA-06512: at "SYS.DBMS_STATS", line 15638
ORA-06512: at line 1

使用RMAN blockreocver命令试图修改该物理坏块:

RMAN> blockrecover datafile 4 block 870212;

Starting blockrecover at 08-NOV-12

channel ORA_DISK_1: restored block(s) from backup piece 1
piece handle=/s01/flash_recovery_area/G10R25/backupset/2012_08_06/o1_mf_nnndf_TAG20120806T075500_81zd4njn_.bkp tag=TAG20120806T075500
channel ORA_DISK_1: block restore complete, elapsed time: 00:01:16

starting media recovery

archive log thread 1 sequence 467 is already on disk as file /s01/flash_recovery_area/G10R25/archivelog/2012_10_31/o1_mf_1_467_893571cm_.arc
archive log thread 1 sequence 468 is already on disk as file /s01/flash_recovery_area/G10R25/archivelog/2012_10_31/o1_mf_1_468_893pc84l_.arc
archive log thread 1 sequence 469 is already on disk as file /s01/flash_recovery_area/G10R25/archivelog/2012_11_01/o1_mf_1_469_894zsbym_.arc
archive log thread 1 sequence 470 is already on disk as file /s01/flash_recovery_area/G10R25/archivelog/2012_11_01/o1_mf_1_470_896b944y_.arc
4_.arc
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of blockrecover command at 11/08/2012 06:19:40
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 466 lowscn 27762151 found to restore
RMAN-06025: no backup of log thread 1 seq 465 lowscn 27762145 found to restore
RMAN-06025: no backup of log thread 1 seq 464 lowscn 27762142 found to restore

由于缺少必要的归档日志导致blockrecover无法成功,需要另想办法。

首先确认该数据块属于哪个SEGMENT,如果是INDEX那么完全可以重建也不会丢失数据,但是如果是表数据则需要容忍丢失该坏块内的数据:
SQL> col tablespace_name for a20
SQL> col segment_type for a10
SQL> col segment_name for a20
SQL> col owner for a8
SQL> SELECT tablespace_name, segment_type, owner, segment_name
2 FROM dba_extents
3 WHERE file_id = &fileid
4 and &blockid between block_id AND block_id + blocks - 1;
Enter value for fileid: 4
old 3: WHERE file_id = &fileid
new 3: WHERE file_id = 4
Enter value for blockid: 870212
old 4: and &blockid between block_id AND block_id + blocks - 1
new 4: and 870212 between block_id AND block_id + blocks - 1

TABLESPACE_NAME SEGMENT_TY OWNER SEGMENT_NAME
-------------------- ---------- -------- --------------------
USERS TABLE SYS CORRUPT_ME

SQL> select count(*) from CORRUPT_ME;
select count(*) from CORRUPT_ME
*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 870212)
ORA-01110: data file 4:
'/s01/oradata/G10R25/datafile/o1_mf_users_7ch7d4nx_.dbf'

SQL> analyze table corrupt_me validate structure;
analyze table corrupt_me validate structure
*
ERROR at line 1:
ORA-01498: block check failure - see trace file

SQL> oradebug setmypid
Statement processed.