在oracle 9i里，进行如下的测试:
引用:db_tns =
(DESCRIPTION =
(failover = on )
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.100)(PORT = 1521)) --第一个IP不存在
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.120)(PORT = 1521)) --这个IP此时是主库
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = test)
)
)
db_stb:/u01/oracle/product/9.2/network/admin>$tnsping db_tns
TNS Ping Utility for IBM/AIX RISC System/6000: Version 9.2.0.6.0 - Production on 04-AUG-2008 13:59:02
Copyright (c) 1997 Oracle Corporation. All rights reserved.
Used parameter files:
/u01/oracle/product/9.2/network/admin/sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (failover = on) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.100)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.120)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SID = test)))
OK (76380 msec) --这里总共花了76秒钟
在10g里，如果配置了双IP,如果第一个IP不存在，tnsping的速度也快了许多，在本次测试中，只需要3秒钟就转到第二个IP上来了。
引用:db_tns =
(DESCRIPTION =
(failover = on )
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.100)(PORT = 1521)) --第一个IP不存在
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.120)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = test)
)
)
[oracle@dbtest admin]$ tnsping db_tns
TNS Ping Utility for Linux: Version 10.2.0.4.0 - Production on 04-AUG-2008 13:36:23
Copyright (c) 1997, 2007, Oracle. All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (failover = on) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.100)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.168.120)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SID = test)))
OK (3010 msec)
看来ORACLE，还是在不断改进的。