ora-01578

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.
SQL> oradebug tracefile_name
/s01/admin/G10R25/udump/g10r25_ora_19749.trc

Corrupt block relative dba: 0x010d4744 (file 4, block 870212)
Bad header found during buffer read
Data in bad block:
 type: 6 format: 2 rdba: 0x000d4744
 last change scn: 0x0000.00000000 seq: 0xff flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x000006ff
 check value in block header: 0x6323
 computed block checksum: 0x0
Reread of rdba: 0x010d4744 (file 4, block 870212) found same corrupted data
*** 2012-11-08 06:23:12.564
table scan: segment: file# 4 block# 870211
            skipping corrupt block file# 4 block# 870212
*** 2012-11-08 06:23:36.955
table scan: segment: file# 4 block# 870211
            skipping corrupt block file# 4 block# 870212
skipping corrupted block at rdba: 0x010d4744

下面使用10231 level 10事件来避免发生ORA-01578错误，并将原坏块表复制出来:

SQL> alter session set events '10231 trace name context forever,level 10';

Session altered.

SQL>  select count(*) from CORRUPT_ME;

  COUNT(*)
----------
     50857

SQL> create table corrupt_me_copy tablespace users as select * from  CORRUPT_ME;

Table created.

SQL> analyze table corrupt_me_copy validate  structure;

Table analyzed.

之后仅需要将新表rename为旧表，并重建索引即可：

SQL>  alter table corrupt_me rename to corrupt_me_copy1;

Table altered.

SQL> alter table corrupt_me_copy rename to corrupt_me;

Table altered.

SQL> rebuild indexs