现象：oracle10gr2.0.0.1升级后，现在客户端连接时报ora-12520错误12520, 00000, quot;tns:listener could not find available
现象：
oracle10gr2.0.0.1升级后，现在客户端连接时报ora-12520错误
12520, 00000, tns:listener could not find available handler for requested type of server
// *cause: none of the known and available service handlers for requested type
// of server (dedicated or shared) are appropriate for the client connection.
// *action: run lsnrctl services to ensure that the instance(s) have
// registered with the listener and that the appropriate handlers are
// accepting connections.
解决：
在网上找了资料后修改了下面的参数后正常：
sql> alter system set local_listener = '(address=(protocol=tcp)(host=172.0.2.62)(port=1521))'
2 scope = spfile sid = 'rac11g1';
系统已更改。
sql> alter system set local_listener = '(address=(protocol=tcp)(host=172.0.2.63)(port=1521))'
2 scope = spfile sid = 'rac11g2';
系统已更改。
sql> shutdown immediate数据库已经关闭。已经卸载数据库。
oracle 例程已经关闭。
sql> startup
oracle 例程已经启动。
total system global area 1.7108e+10 bytes
fixed size 2101632 bytes
variable size 3814182528 bytes
database buffers 1.3288e+10 bytes
redo buffers 4431872 bytes数据库装载完毕。数据库已经打开。
另外的节点也重启数据库服务器。
sql> conn system/test@rac已连接。
问题解决。
另外：在打数据库补丁后，，在启动数据库时遇到了下面的错误：
sql> startup
ora-00119: invalid specification for system parameter local_listener
ora-00132: syntax error or unresolved network name 'listener_ge02'
解决方法如下：
1、关闭数据库；
sql> shutdown abort
oracle instance shut down.
2、然后在修改/opt/oracle/product/10.2.0/network/admin/tnsnames.ora文件，添加下面的语句：
listener_ge02 =
(address = (protocol = ipc)(key = extproc0))
3、然后重新启动数据库
sql> startup
oracle instance started.
total system global area 285212672 bytes
fixed size 1218992 bytes
variable size 92276304 bytes
database buffers 188743680 bytes
redo buffers 2973696 bytes
database mounted.
database opened.