以dba身份登录sqlplus环境

select count(*) from v$process //获取当前活动的进程数目

修改$ORACLE_HOME/dbs/init.ora中init.ora文件

查看、修改ORACLE最大进程数
查看ORACLE最大进程数：
SQL> select count(*) from v$session? #连接数
SQL> Select count(*) from v$session where status='ACTIVE'　#并发连接数
SQL> show parameter processes? #最大连接
SQL> alter system set processes = value scope = spfile;重启数据库? #修改连接

unix 1个用户session 对应一个操作系统 process
而 windows体现在线程

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修改ORACLE最大进程数：
使用sys，以sysdba权限登录：

SQL> show parameter processes;

NAME???????????????????????????????? TYPE??????? VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes????????????????????? integer???? 1
db_writer_processes????????????????? integer???? 1
job_queue_processes????????????????? integer???? 10
log_archive_max_processes??????????? integer???? 1
processes??????????????????????????? integer???? 150

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

系统已更改。

SQL> show parameter processes;

NAME???????????????????????????????? TYPE??????? VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes????????????????????? integer???? 1
db_writer_processes????????????????? integer???? 1
job_queue_processes????????????????? integer???? 10
log_archive_max_processes??????????? integer???? 1
processes??????????????????????????? integer???? 150

SQL> create pfile from spfile;

文件已创建。
?

重启数据库，
?
SQL> show parameter processes;

NAME???????????????????????????????? TYPE??????? VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes????????????????????? integer???? 1
db_writer_processes????????????????? integer???? 1
job_queue_processes????????????????? integer???? 10
log_archive_max_processes??????????? integer???? 1
processes??????????????????????????? integer???? 300
?
搞定!