发现有的时候，EBS会报连接数不足的问题。所以尝试着提高了processes和sessions，EBS安装完之后，数据库init参数processes默认为200,sessions默认为400.这里我把DB的processes和sessions提高到了500和1000。
processes = 500 # Max. no. of users x 2
sessions = 1000 # 2 X processes
修改完之后，重启DB，参数就会生效。
addbctl.sh stop
addbctl.sh start
查看参数设置
show parameter processes
show parameter sessions
文章Oracle EBS DB Init Parameters里（见 http://www.linuxidc.com/Linux/2012-07/64847.htm ），有提到Oracle提供一个init parameter参考的设置。
关于Processes和sessions parameters,init.ora有相关描述
#########
#
# Processes and sessions parameters
#
# A database process can be associated with one or more database
# sessions. For all technology stack components other than Oracle
# Forms, there is a one-to-one mapping between sessions and processes.
#
# For Forms processes, there will be one database session per
# open form, with a minimum of two sessions per Forms user (one
# for the navigator form, and one for the active form).
#
# The sessions parameter should be set to twice the value of the
# processes parameter.
#
#########
另外如何查询当下数据的连接数和最大连接数
--当前的连接数
select count(*) from v$process;
--设置的最大连接数（默认值为200）
select value from v$parameter where name = 'processes';
------------------------------------------------
--查看当前的session使用情况
SELECT Count(*) FROM v$session;
或
SELECT username, machine, program, status, COUNT (machine) AS
FROM v$session
GROUP BY username, machine, program, status
ORDER BY machine;
--查看系统最大session数
select value from v$parameter where name = 'sessions';