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.
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> rebuild indexs
本文转自maclean_007 51CTO博客，原文链接:
http://blog.51cto.com/maclean/1278161
