查看一下数据库现有的进程数，是否已经达到参数processes的大小。

?? -- select count(*) from v$process;? 取得数据库目前的进程数。
?? -- select value from v$parameter where name = 'processes'; 取得进程数的上限

(1)查看当前会话数、processes和sessions值，发现session数14和processes值150已经非常接近
SQL> select count(*) from v$session;

? COUNT(*)
----------
?????? 146

SQL> show parameter processes

NAME???????????????????????????????? TYPE?????????????????? VALUE
------------------------------------ ------------------------------


aq_tm_processes????????????????????? integer??????????????? 0

db_writer_processes????????????????? integer??????????????? 2

gcs_server_processes???????????????? integer??????????????? 0

job_queue_processes????????????????? integer??????????????? 10

log_archive_max_processes??????????? integer??????????????? 2

processes??????????????????????????? integer??????????????? 150

(2) Modify the two parameter(processes,sessions)

SQL> alter system set processes=300 scope=spfile;

System altered.

SQL> alter system set sessions=335 scope=spfile;

System altered.

(3) Let's shutdown and startup database in order to let the two parameter taken effect.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup?????? ?
ORACLE instance started.

Total System Global Area 1610612736 bytes
Fixed Size????????????????? 2030456 bytes
Variable Size???????????? 989856904 bytes
Database Buffers????????? 603979776 bytes
Redo Buffers?????????????? 14745600 bytes
Database mounted.
Database opened.
SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
$ sqlplus /nolog

(4) test the result.

SQL*Plus: Release 10.2.0.3.0 - Production on 星期五 12月 9 09:53:13 2011

Copyright (c) 1982, 2006, Oracle.? All Rights Reserved.

SQL> conn sys/oracle@orcl as sysdba
Connected.
SQL>

--the end.