异常：
DB: Oracle 11.2.0.1 –版本够low的
五一假期时给用户DB做了switch over主备切换后，用了发现切换后新的主库DB中报错如下：
Wed May 08 09:44:14 2019
Errors in file /u01/product/diag/rdbms/new/orcl/trace/orcl_ora_100843.trc (incident=50865):
ORA-01578: ORACLE 資料區塊損毀 (檔案編號 126, 區塊編號 4969)
ORA-01110: 資料檔 126: '/data/orcl/smt_idx01.dbf'
ORA-26040: 已使用 NOLOGGING 選項載入資料區塊
Incident details in: /u01/product/diag/rdbms/new/orcl/incident/incdir_50865/orcl_ora_100843_i50865.trc
========= Dump for incident 50865 (ORA 1578) ========
*** 2019-05-08 09:44:14.254
dbkedDefDump(): Starting incident default dumps (flags=0x2, level=3, mask=0x0)
—– Current SQL Statement for this session (sql_id=52s3v0xvc21j8) —–
SELECT
ROWID, STATION_NUMBER, MACHINE_CODE, PRODUCT_NO,
VER, EMP_NO, FEEDER_NO,
KEY_PART_NO, WORK_TIME, SN,
LINE_NAME, MO_NO, SIDE,
LOT_NO, VENDOR, DATE_CODE,
FEEDER_ID, KEY_PART_QTY, HH_PN,
PACKED_QTY, MFG_PN, PKG_ID,
CPL_ID, END_TIME, BOM_NO,
CUST_PN, DIFFERENCE_QTY, USED_QTY
FROM SFISM4.R_SMT_LOG
Where
PKG_ID = 'VCI3011808R05ZI'
分析：
ORA-01578，
ORA-01110
第一反应是有数据坏块
使用DBV检查坏块
$dbv file=/data/orcl/smt_idx01.dbf BLOCKSIZE=16384
DBVERIFY: Release 11.2.0.1.0 – Production on Wed May 8 16:15:12 2019
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
DBVERIFY – Verification starting : FILE = /data/orcl/smt_idx01.dbf
DBV-00201: Block, DBA 528482373, marked corrupt for invalid redo application
DBV-00201: Block, DBA 528482374, marked corrupt for invalid redo application
DBV-00201: Block, DBA 528482375, marked corrupt for invalid redo application
….
DBVERIFY – Verification complete
Total Pages Examined : 294400
Total Pages Processed (Data) : 0
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 259171
Total Pages Failing (Index): 0
Total Pages Processed (Other): 19965
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 15264
Total Pages Marked Corrupt : 3
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 2390574971 (2791.2390574971)
DBV-00201
意味着主库到备库中部分redo没有应用到datafile，
检查切换之前的主库(现在的备库) 果然datafile
'/data/orcl/smt_idx01.dbf'
没有应用
SELECT NAME, UNRECOVERABLE_CHANGE# FROM V$DATAFILE
where UNRECOVERABLE_CHANGE# >0
此类问题通常是因为主库中一些nologging的操作导致redo 没能到备库应用，
结合之前alert.log 的报错“
ORA-26040: 已使用 NOLOGGING 選項載入資料區塊” ，基本确认了这个问题。
难道data guard 没用开到force logging模式导致类似append 操作没用同步？
select force_logging from v$database;
查询
force_logging
为NO还真没用启用
force logging…
解决：
检查
NOLOGGING影响
没用同步datafile对应的segment：
select * from dba_extents
where file_id=126 and 4969 between block_id AND block_id + blocks – 1;
还好segment全部是index，rebuild index即可解决。
注：如果是table 或其它文件需要对原主库(现备库)的datafile backup再至现主库(原备库)中还原恢复了。
最后，老生常谈建立standby，一定记得开启强制归档避免问题发生：
alter database force logging;
