一 restrict 登陆
SQL> startup restrict
ORACLE instance started.

Total System Global Area  188743680 bytes
Fixed Size                   788068 bytes
Variable Size             145488284 bytes
Database Buffers           41943040 bytes
Redo Buffers                 524288 bytes
Database mounted.
Database opened.

SQL> conn zz/a850624
ERROR:
ORA-01035: ORACLE only available to users with RESTRICTED SESSION privilege
必须要  RESTRICTED SESSION privilege
SQL> alter system disable restricted session;

System altered.
SQL> conn zz/a850624
Connected.
SQL>

二 QUIESCE DATABASE登陆

SQL> select active_state from v$instance;

ACTIVE_ST
---------
NORMAL~~~~~~~~~~~~~~正常

SQL> show parameter resource

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
enqueue_resources                    integer     968
resource_limit                       boolean     TRUE
resource_manager_plan                string~~~~~~~~~~~~~~~~~~要求是活动的 资源计划
                                                          他是用数据库资源管理器控制                                                                         

instance

SQL> show parameter resource

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
enqueue_resources                    integer     968
resource_limit                       boolean     TRUE
resource_manager_plan                string      SYSTEM_PLAN*******************

SQL> alter system quiesce restricted;

System altered.

SQL> select active_state from v$instance;

ACTIVE_ST
---------
QUIESCED

SQL> conn xh/a831115
会等待 hung住了\

SQL> alter system unquiesce;~~~另一个SESSION  SYSDBA登陆

System altered.

SQL>

SQL> conn xh/a831115       hang的连接成功
Connected.

SQL> select active_state from v$instance;  SYSDBA登陆

ACTIVE_ST
---------
NORMAL

SQL> alter system quiesce restricted;~~~~~~~~~SYSDBA

System altered.

SQL> select * from t1;~~~~~~~~~ USER   XH 执行后又hung住了

SQL> alter system unquiesce;    SYSDBA

System altered.

SQL> select * from t1; USER XH  output

         A
----------
         2
         2
         2
         2
         2

SQL> update  t1 set a=6;~~~~~~~~~~USER XH

15 rows updated.~~~~~~~~未commit

SQL>

SQL> alter system quiesce restricted; SYSDBA HANG 等待 所有事务执行完毕
SQL> commit; XH

Commit complete.

SQL> alter system quiesce restricted; SYSDBA

System altered.

SQL> select sid,state from v$session where username='XH';

       SID STATE
---------- -------------------
       161 WAITING~~~~~~~~~~~~~~~~~~~~状态

SQL> select sid ,event from v$session_event where event like '%QUIESCE%';
可以确定 那些SESSION  WAITING quiesce database

当停顿了数据库，INTERNAL_QUIESCE资源计划被激活了。除SYS_GROUPS其它所有的资源组中的ACTIVE_SESS_POOL_P1应被设置为0。因SYS和SYSTEM用户都属于SYS_GROUPS组，所以只

有它们可以连接到数据库。