数据库关闭与启动： scn == system change number

数据库启动步骤

nomount----> mount---->open

(1)第一阶段

sql> startup nomount

ORACLE instance started.

Total System Global Area 7148580864 bytes

Fixed Size 2214216 bytes

Variable Size 3825206968 bytes

Database Buffers 3288334336 bytes

Redo Buffers 32825344 bytes

sql>

sql> select status from v$instance;

STATUS

------------

STARTED

sql> show parameter spfile;

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

spfile string +DATA/orcl/spfileorcl.ora

nomount这一步，数据库做了什么？

读取参数文件+启动数据库实例

(2)第二阶段

sql> alter database mount;

Database altered.

sql>

sql> show parameter control

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

control_file_record_keep_time integer 7

control_files string +DATA/orcl/controlfile/current

.260.943301383,+FRA/orcl/cont

rolfile/current.256.943301385

control_management_pack_access string DIAGNOSTIC+TUNING

sql> select status from v$instance;

STATUS

------------

MOUNTED

sql> select name from v$datafile;

NAME

--------------------------------------------------------------------------------

+DATA/orcl/datafile/system.256.943301251

+DATA/orcl/datafile/sysaux.257.943301251

+DATA/orcl/datafile/undotbs1.258.943301251

+DATA/orcl/datafile/users.259.943301251

+DATA/orcl/datafile/example.265.943301433

sql> select member from v$logfile;

MEMBER

--------------------------------------------------------------------------------

+DATA/orcl/onlinelog/group_3.263.943301403

+FRA/orcl/onlinelog/group_3.259.943301407

+DATA/orcl/onlinelog/group_2.262.943301397

+FRA/orcl/onlinelog/group_2.258.943301401

+DATA/orcl/onlinelog/group_1.261.943301389

+FRA/orcl/onlinelog/group_1.257.943301395

select name from v$tablespace;

select name from v$database;

sql> select name from v$database;

NAME

---------

ORCL

sql> show parameter name

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

db_file_name_convert string

db_name string orcl

db_unique_name string orcl

global_names boolean FALSE

instance_name string orcl

lock_name_space string

log_file_name_convert string

service_names string orcl

sql>

mount这一步，数据库做了什么？

读取控制文件,验证控制文件的一致性及db_name的一致性

(3)第三阶段

sql> alter database open;

Database altered.

sql> select open_mode from v$database;

OPEN_MODE

--------------------

READ WRITE

sql> select status from v$instance;

STATUS

------------

OPEN

open这一步，数据库做了什么？

验证数据文件和联机重做日志是否存在及控制文件、数据文件的一致性

sql> startup

ORACLE instance started.

Total System Global Area 7148580864 bytes

Fixed Size 2214216 bytes

Variable Size 3825206968 bytes

Database Buffers 3288334336 bytes

Redo Buffers 32825344 bytes

Database mounted.

Database opened.

###############

使用oracle Restart组件中的 SRVCTL 工具来启动数据库

srvctl start database -d orcl -o mount

srvctl start database -d orcl -o start

srvctl start database -d orcl -o open

不加 -o 默认是open

srvctl start database -d orcl 等价于

srvctl start database -d orcl -o open

[oracle@oel ~]$ crs_stat -t

Name Type Target State Host

------------------------------------------------------------

ora.DATA.dg ora....up.type ONLINE ONLINE oel

ora.FRA.dg ora....up.type ONLINE ONLINE oel

ora....ER.lsnr ora....er.type ONLINE ONLINE oel

ora.asm ora.asm.type ONLINE ONLINE oel

ora.cssd ora.cssd.type ONLINE ONLINE oel

ora.diskmon ora....on.type ONLINE ONLINE oel

ora.orcl.db ora....se.type ONLINE ONLINE oel

#############

数据库关闭：

其他：

查看oracle内存段：

ipcs -m | grep ora

[root@oel ~]# ipcs -m | grep ora

0xfa55c7d8 163841 oracle 660 4096 0

0x00000000 1736706 oracle 660 4096 0

0x00000000 1769475 oracle 660 4096 0

0xd3ac6c80 1802244 oracle 660 4096 0

ps - ef | grep ora