在用户使用ORACLE EBS 12R的时候，发现提示出错：用户名，密码或数据库无效。表单没办法弹出来。
登录数据库：
SQL> conn apps/apps
ERROR:
ORA-12516: TNS:listener could not find available handler with matching protocol
stack
登录不上数据库，查找ORA-12516的错误：
TNS-12516 TNS:listener could not find available handler with matching protocol stack

Cause: None of the known and available service handlers for the given SERVICE_NAME support the client's protocol stack: transport, session, and presentation protocols.

Action: Check to make sure that the service handlers (for example, dispatchers) for the given SERVICE_NAME are registered with the listener, are accepting connections, and that they are properly configured to support the desired protocols.

要求一些用户退出应用系统，然后登录
SQL>show parameter proccess;
参数的值为：200
SQL>SELECT COUNT(*) FROM V$PROCESS;
返回的值为：199
查看ORACLE的警告日志文件，报进程无法创建的错误：
Tue Jun 19 19:00:45 2007
ksvcreate: Process(m000) creation failed
Tue Jun 19 19:01:16 2007
Process J000 died, see its trace file
Tue Jun 19 19:01:16 2007
kkjcre1p: unable to spawn jobq slave process
Tue Jun 19 19:01:16 2007
Errors in file /ebs/d02/oracle/VIS/db/tech_st/10.2.0/admin/VIS_demo/bdump/vis_cjq0_4501.trc:

由上可以看出PROCESS参数设置过小，调整这个参数的值为：400,同时SESSION的参数也作调整。
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