show parameter processes;?
然后?
更改系统连接数?
alter system set processes=1000 scope=spfile;?
下面是具体的操作步骤与说明
问题描述：客户端连接数据库报错?
ORA-12516: TNS: 监听程序无法找到匹配协议栈的可用句柄?
解决过程：?
1。查看当前会话数、processes和sessions值，发现session数和2个参数的值已经非常逼近?
SQL*Plus: Release 10.2.0.1.0 - Production on 星期一 10月 9 15:50:21 2006?
Copyright (c) 1982, 2005, Oracle. All rights reserved.?
SQL> conn / as sysdba?
已连接。?
SQL> select count(*) from v＄session;?
COUNT(*)?
----------?
45?

SQL> show parameter processes?
NAME TYPE VALUE?
------------------------------------ ----------- ----------------------?
aq_tm_processes integer 0?
db_writer_processes integer 1?
gcs_server_processes integer 0?
job_queue_processes integer 10?
log_archive_max_processes integer 2?
processes integer 50?
SQL> show parameter sessions?
NAME TYPE VALUE?
------------------------------------ ----------- ----------------------?
java_max_sessionspace_size integer 0?
java_soft_sessionspace_limit integer 0?
license_max_sessions integer 0?
license_sessions_warning integer 0?
logmnr_max_persistent_sessions integer 1?
sessions integer 60?
shared_server_sessions integer?

2。修改processes和sessions值?
SQL> alter system set processes=300 scope=spfile;?
系统已更改。?
SQL> alter system set sessions=300 scope=spfile;?
系统已更改。?

3。查看processes和sessions参数，但更改并未生效?
SQL> show parameter processes?
NAME TYPE VALUE?
------------------------------------ ----------- ----------------------?
aq_tm_processes integer 0?
db_writer_processes integer 1?
gcs_server_processes integer 0?
job_queue_processes integer 10?
log_archive_max_processes integer 2?
processes integer 50?
SQL> show parameter sessions?