现象：
客户的数据库（RAC环境：11.1.0.6）发生了实例异常宕机现象，伴随有ORA-07445错误：
Sun Jun 23 01:00:06 2013
Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0xF] [PC:0x755773D, kcbw_get_bh()+67]
Errors in file /Oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_mman_2015.trc (incident=298938):
ORA-07445: exception encountered: core dump [kcbw_get_bh()+67] [SIGSEGV] [ADDR:0xF] [PC:0x755773D] [Address not mapped to object] []
Incident details in: /oracle/app/11gR1/diag/rdbms/xij/xij1/incident/incdir_298938/xij1_mman_2015_i298938.trc
Sun Jun 23 01:00:07 2013
Trace dumping is performing id=[cdmp_20130623010007]
Sun Jun 23 01:00:09 2013
Sweep Incident[298938]: completed
Sun Jun 23 01:00:09 2013
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_pmon_1981.trc:
ORA-00822: MMAN process terminated with error
PMON (ospid: 1981): terminating the instance due to error 822
Sun Jun 23 01:00:09 2013
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_j000_22268.trc:
ORA-00822: MMAN process terminated with error
Sun Jun 23 01:00:09 2013
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_m000_22430.trc:
ORA-00822: MMAN process terminated with error
System state dump is made for local instance
System State dumped to trace file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_diag_1987.trc
Sun Jun 23 01:00:09 2013
ORA-1092 : opiodr aborting process unknown ospid (11096_47524616916112)
Sun Jun 23 01:00:09 2013
ORA-1092 : opitsk aborting process
Sun Jun 23 01:00:09 2013
ORA-1092 : opiodr aborting process unknown ospid (6317_47353365785744)
Sun Jun 23 01:00:09 2013
ORA-1092 : opitsk aborting process
Sun Jun 23 01:00:09 2013
ORA-1092 : opiodr aborting process unknown ospid (28698_47056912551056)
Sun Jun 23 01:00:09 2013
ORA-1092 : opitsk aborting process
Sun Jun 23 01:00:09 2013
ORA-1092 : opiodr aborting process unknown ospid (18927_47567504653456)
Sun Jun 23 01:00:10 2013
ORA-1092 : opitsk aborting process
Sun Jun 23 01:00:10 2013
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_q001_3487.trc:
ORA-00822: MMAN process terminated with error
ORA-1092 : opidrv aborting process Q001 ospid (3487_47252506410128)
Sun Jun 23 01:00:11 2013
ORA-1092 : opitsk aborting process
Sun Jun 23 01:00:11 2013
License high water mark = 510
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_m000_22430.trc:
ORA-00822: MMAN process terminated with error
ORA-00822: MMAN process terminated with error
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_j000_22268.trc:
ORA-00449: background process 'LGWR' unexpectedly terminated with error 822
ORA-00822: MMAN process terminated with error
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_j000_22268.trc:
ORA-00449: background process 'LGWR' unexpectedly terminated with error 822
ORA-00822: MMAN process terminated with error
Errors in file /oracle/app/11gR1/diag/rdbms/xij/xij1/trace/xij1_j000_22268.trc:
ORA-00604: error occurred at recursive SQL level 1
ORA-00822: MMAN process terminated with error
ORA-06512: at "WKSYS.WK_JOB", line 442
ORA-00449: background process 'MMON' unexpectedly terminated with error 822
ORA-00822: MMAN process terminated with error
ORA-06512: at line 1
ORA-1092 : opidrv aborting process J000 ospid (22268_47357930925200)
Sun Jun 23 01:00:20 2013
Instance terminated by PMON, pid = 1981
Sun Jun 23 01:00:21 2013
USER (ospid: 22527): terminating the instance
Instance terminated by USER, pid = 22527
Sun Jun 23 01:00:26 2013
Starting ORACLE instance (normal)
分析：
Ora-07445通常是Oracle自身的BUG导致的，
首先使用IPS收集了alert中的错误信息（IPS使用方法见我的另一篇文章《IPS简单使用方法》）：
搜寻了一下metalink，发现客户的问题跟以下三篇Note中描述的BUG类似：
ORA-7445 (kcbw_get_bh) [ID 1341402.1]
Bug 9728912 [https://bug.oraclecorp.com/pls/bug/webbug_edit.edit_info_top?rptno=9728912] - PMON terminates instance due to ORA-7445 [kcbw_numperchunk] / ORA-7445 [kcbw_get_bh]] [ID 9728912.8]
Instance Crashed On ORA-7445 kcbw_numperchunk [ID 1364264.1]
但根据Note可以看到，相关的BUG已经在11.1.0.6中fix掉了。
看看客户数据库中的其余严重错误信息：
Node1:
adrci> show problem
ADR Home = /oracle/app/11gR1/diag/rdbms/xij/xij1:
*************************************************************************
PROBLEM_ID PROBLEM_KEY LAST_INCIDENT LASTINC_TIME
-------------------- ----------------------------------------------------------- -------------------- ----------------------------------------
5 ORA 7445 [kcbw_get_bh()+67] 298938 2013-06-23 01:00:06.373716 +08:00
11 ORA 600 276161 2013-06-04 18:12:12.709933 +08:00
10 ORA 600 [729] 276160 2013-06-04 18:09:27.857128 +08:00
7 ORA 7445 [kgghash()+367] 253234 2013-06-03 15:27:04.349337 +08:00
9 ORA 7445 [kksMapCursor()+323] 256538 2013-05-27 09:54:58.684956 +08:00
8 ORA 7445 [qkabxo()+22] 251194 2013-05-01 22:03:37.715416 +08:00
2 ORA 600 [kghfrh:ds] 238818 2013-01-28 11:35:23.755034 +08:00
6 ORA 7445 [eoa_pm_push()+31] 239218 2013-01-28 11:24:42.835685 +08:00
3 ORA 7445 [ioei_get_method_counts()+39] 71129 2012-10-17 11:17:39.735719 +08:00
4 ORA 7445 [jol_calculate_transitive_interface_set()+1165] 74233 2012-10-17 11:05:51.570021 +08:00
1 ORA 600 [kghfru:ds] 6369 2012-09-07 17:35:55.001585 +08:00
11 rows fetched
Node2:
[oracle@XIJ02 ~]$ adrci
ADRCI: Release 11.1.0.6.0 - Beta on Mon Jun 24 14:59:37 2013