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Oracle数据库启动的四个阶段

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Jun 07, 2016 pm 05:12 PM

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Oracle数据库启动的四个阶段，见下图: 1. 数据库处于SHUTDOWN状态在此种状态，数据库处于停止状态。不能接受外界数据请求。使用

Oracle数据库启动的四个阶段，见下图:

1. 数据库处于SHUTDOWN状态

在此种状态，数据库处于停止状态。不能接受外界数据请求。使用操作系统命令ps –ef | grep ora看不到任何数据库进程的存在。

2. 数据库处于NOMOUNT状态

在此种状态，数据库后台进程已经建立。并根据参数文件中关于SGA的相关参数，，建立共享内存区和缺省的oracle数据库进程。并同时检查相关初始化参数的正确性。

使用操作系统命令可以考到相应的进程。ps –ef | grep ora_ 并且使用ipcs –m命令可以看到以oracle用户建立起来的共享内存区。

oracle@db1:~> sqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on Sat Mar 3 22:48:27 2012

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 167772160 bytes
Fixed Size                  1218316 bytes
Variable Size             104859892 bytes
Database Buffers           58720256 bytes
Redo Buffers                2973696 bytes
SQL>

查看进程状态.

oracle@db1:~> ps -ef | grep ora_
oracle 3626 1 0 22:48 ? 00:00:00 ora_pmon_orcl1
oracle 3628 1 0 22:48 ? 00:00:00 ora_psp0_orcl1
oracle 3630 1 0 22:48 ? 00:00:00 ora_mman_orcl1
oracle 3632 1 0 22:48 ? 00:00:00 ora_dbw0_orcl1
oracle 3634 1 0 22:48 ? 00:00:00 ora_lgwr_orcl1
oracle 3636 1 0 22:48 ? 00:00:00 ora_ckpt_orcl1
oracle 3638 1 0 22:48 ? 00:00:00 ora_smon_orcl1
oracle 3640 1 0 22:48 ? 00:00:00 ora_reco_orcl1
oracle 3642 1 0 22:48 ? 00:00:00 ora_cjq0_orcl1
oracle 3644 1 0 22:48 ? 00:00:00 ora_mmon_orcl1
oracle 3646 1 0 22:48 ? 00:00:00 ora_mmnl_orcl1
oracle 3648 1 0 22:48 ? 00:00:00 ora_d000_orcl1
oracle 3650 1 0 22:48 ? 00:00:00 ora_s000_orcl1
oracle 3669 3652 0 22:50 pts/2 00:00:00 grep ora_
oracle@db1:~>
oracle@db1:~> ipcs -m

------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0xe835086c 458764 oracle 640 171966464 14

oracle@db1:~>

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