这个错误发生在11.1.0.6版本中。简单记录一下bug的现象。

首先记录一下错误信息：

Fatal NI connect error 12532, connecting to:
(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.4.70)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=ora11g_s.ytk-thinkpad)(CID=(PROGRAM=oracle)(HOST=yangtk.ytk-thinkpad)(USER=oracle))))

VERSION INFORMATION:
TNS for Linux: Version 11.1.0.6.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.1.0.6.0 - Production
Time: 05-SEP-2007 18:57:32
Tracing not turned on.
Tns error struct:
ns main err code: 12532

TNS-12532: TNS:invalid argument
ns secondary err code: 12560
nt main err code: 502

TNS-00502: Invalid argument
nt secondary err code: 113
nt OS err code: 0
Error 12532 received logging on to the standby
Errors in file /data/oracle/diag/rdbms/ora11g_p/ora11g/trace/ora11g_arc0_2794.trc:
ORA-12532: TNS:invalid argument
PING[ARC0]: Heartbeat failed to connect to standby 'ora11g_s'. Error is 12532.
Wed Sep 05 19:01:06 2007
Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0x0] [PC:0x924BFFE, koioapm()+254]
Errors in file /data/oracle/diag/rdbms/ora11g_p/ora11g/trace/ora11g_mmon_2780.trc (incident=13313):
ORA-07445: exception encountered: core dump [koioapm()+254] [SIGSEGV] [ADDR:0x0] [PC:0x924BFFE] [Address not mapped to object] []
Incident details in: /data/oracle/diag/rdbms/ora11g_p/ora11g/incident/incdir_13313/ora11g_mmon_2780_i13313.trc

问题发生在主库尝试归档到STANBY数据库失败之后。自错误发生之后，每次尝试连接STANDBY数据库报错后，都会出现这个7445错误。且主库重启之后，问题消失。

根据上面的信息判断，初步断定和STANDBY环境有关。由于问题无法重新，猜测是由于某些状态不正确引起的。

从7445错误的trace文件中找不到什么有价值的信息：

$ more /data/oracle/diag/rdbms/ora11g_p/ora11g/trace/ora11g_mmon_4154.trc
Trace file /data/oracle/diag/rdbms/ora11g_p/ora11g/trace/ora11g_mmon_4154.trc
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /data/oracle/product/11.1
System name: Linux
Node name: yangtk.ytk-thinkpad
Release: 2.6.18-8.el5
Version: #1 SMP Tue Jun 5 23:11:13 EDT 2007
Machine: i686
Instance name: ora11g
Redo thread mounted by this instance: 1
Oracle process number: 26
Unix process pid: 4154, image: oracle@yangtk.ytk-thinkpad (MMON)

*** 2007-09-05 19:14:04.120
*** SESSION ID:(129.238) 2007-09-05 19:14:04.120
*** CLIENT ID:() 2007-09-05 19:14:04.120
*** SERVICE NAME:(SYS$BACKGROUND) 2007-09-05 19:14:04.120
*** MODULE NAME:() 2007-09-05 19:14:04.120
*** ACTION NAME:() 2007-09-05 19:14:04.120

Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0x0] [PC:0x924BFFE, Exception [type: SIGSEGV, Address not mapped to ob
ject] [ADDR:0x0] [PC:0x924BFFE, koioapm()+254]
DDE: Problem Key 'ORA 7445 [koioapm()+254]' was flood controlled (0x2) (incident: 13409)
ORA-07445: exception encountered: core dump [koioapm()+254] [SIGSEGV] [ADDR:0x0] [PC:0x924BFFE] [Address not mapped to object] []
ssexhd: crashing the process...
Background_Core_Dump = PARTIAL