【翻译自mos文章】在11gR2 rac中启用Dead Connection Connection（DCD）功能

在11gR2 rac中启用Dead Connection Connection（DCD）功能

来源于：
GRID: Dead Connection Connection or DCD and RAC 11.2 (文档 ID 1136945.1)

适用于：
Oracle Net Services - Version 11.2.0.1 and later
Information in this document applies to any platform.
***Checked for relevance on 16-OCT-2013***

目标：
对11gR2的rac 启用Dead Connection Detection (DCD)

译者注：
在10g rac 或者11gR1 rac时代，由于没有$GRID_HOME,因此，启用Dead Connection Detection (DCD)功能时，肯定知道在哪个HOME下设置参数（因为只有一个HOME）
那么到了11gR2时代，由于出现了$GRID_HOME，启用Dead Connection Detection (DCD)是在$GRID_HOME下设置参数？还是在$RDBMS_ORACLE_HOME下设置参数？本文就是用来解答这个疑问的

解决方案：
当启用DCD (SQLNET.EXPIRE_TIME)时，对于11.2 RAC 使用DCD功能时，必须在"RDBMS Oracle home"下被启用。
原因是，scan和tns listener从GRID_HOME下运行，但是bequeath connection归属于RDBMS Oracle home的操作系统用户。

这意味着RDBMS Oracle home下的SQLNET.ORA文件必须被设置，举例如下：
Grid Oracle O/S user "grid"
RDBMS Oracle home O/S user "Oracle"

TNS listeners are running as "grid" user

$ ps -ef |grep tnslsnr
oracle 13858 27102 0 16:22 pts/1 00:00:00 grep tnslsnr
grid 30445 1 0 12:16 ? 00:00:00 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN1 -inherit
grid 31377 1 0 12:20 ? 00:00:00 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit

Make a SQL*Plus connection

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\sqlplus scott/tiger@test

SQL*Plus: Release 11.2.0.1.0 Production on Mon Jun 28 16:24:30 2010

Copyright (c) 1982, 2010, Oracle. All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options

SQL>

得到数据库服务器上的Server Process  ID --->>>23394

SQL> select p.spid, s.serial#, s.username, s.module, s.program, s.machine
from v$process p,v$session s where p.addr = s.paddr and s.username = 'SCOTT';

SPID SERIAL# USERNAME
------------------------ ---------- ------------------------------
MODULE
------------------------------------------------
PROGRAM
------------------------------------------------
MACHINE
----------------------------------------------------------------
23394 56998 SCOTT
SQL*Plus
sqlplus.exe
UK-ORACLE\test

确认23394进程的owner是oracle

$ ps -ef |grep 23394
oracle 23394 1 0 16:24 ? 00:00:00 oraclev11gr21 (LOCAL=NO)
oracle 22927 19181 0 16:25 pts/4 00:00:00 grep 23394