1問題描述：

ORACLE RAC 故障透明切換測試中，連線2個會話，分別被分配到節點1和節點2，關閉節點1的CRS後，已連線到節點1的會話，不會自動切換到節點2 。

但是重新連線的會話會自動到節點2

2問題原因

在配置TNSnames檔案的時候多了一個括號

3查詢括號小竅門

通過ultraEdit查詢匹配括號

ctrl+b

　　寫程式碼的時候，括號一般要一一對應的，但是如果巢狀太多，看花眼了，怎麼辦？你把游標放在括號

開始的地方，按ctrl+b，UE會幫你找到相對應的括號結尾的地方。你還可以試試連著多按幾次ctrl+b

錯誤的   （“ ((FAILOVER_MODE=”的左側多了一個括號）

ITPUX =

  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = itpuxscan)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (FAILOVER = NO)    
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = itpux)
       ((FAILOVER_MODE=
       (TYPE=select) 
       (METHOD = BASIC))
    )

  )

Microsoft Windows [版本 6.1.7601]
版權所有 (c) 2009 Microsoft Corporation。保留所有權利。
C:\Users\Administrator>tnsping itpux

TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 10-12月-2015 17:21:00

Copyright (c) 1997, 2010, Oracle.  All rights reserved.

已使用的引數檔案:
c:\app\Administrator\product\11.2.0\client_2\network\admin\sqlnet.ora

已使用 TNSNAMES 介面卡來解析別名
嘗試連線 (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = itpuxscan)(PORT = 152
1)) (LOAD_BALANCE = yes) (FAILOVER = NO) (CONNECT_DATA = (SERVER = DEDICATED) (S
ERVICE_NAME = itpux) ((FAILOVER_MODE= (TYPE=select) (METHOD = BASIC))))
OK (20 毫秒)


連線2個客戶端

sqlplus /nolog
conn system/[email protected];
select instance_name,status from V$instance;

sqlplus /nolog
conn system/[email protected];
select instance_name,status from V$instance;
SQL> conn system/[email protected];
Connected.
SQL> select instance_name,status from V$instance;

--連線到節點1後，關閉節點1crs後，不會自動切換
INSTANCE_NAME    STATUS
---------------- ------------
itpux1           OPEN

SQL> select instance_name,status from V$instance;
select instance_name,status from V$instance
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 30620
Session ID: 42 Serial number: 9


SQL> select instance_name,status from V$instance;
ERROR:
ORA-03114: not connected to ORACLE

正確的

sqlplus /nolog
conn system/[email protected];
select instance_name,status from V$instance;
ITPUX =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = itpuxscan)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (FAILOVER = NO)    
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = itpux)
       (FAILOVER_MODE=
       (TYPE=select) 
       (METHOD = BASIC))
    )
  )

sqlplus /nolog
conn system/[email protected];
select instance_name,status from V$instance;