Oracle体系结构及备份（十三）——bg-pmon

怼烎@ 2022-01-22 10:09 261阅读 0赞

### 一 什么是PMON进程 ###

The process monitor performs processrecovery when a user process fails. PMON is responsible for cleaning up thecache and freeing resources that the process was using. PMON also checks on thedispatcher processes (described later in this table) and server processes andrestarts them if they have failed.

PMON，进程监控进程（动态注册监听器）

![20130614160430734][]

作用：

清除失败的进程

回滚事务

释放锁

释放其他资源

重启死掉的Dispatchers

### 二 操作示例 ###

oracle@localhost 桌面]$  ps -ef | grep ora_ | grep pmon
    oracle    2889     1  0 17:01 ?        00:00:00 ora_pmon_orcl
    [oracle@localhost 桌面]$ kill -9 2889
    [oracle@localhost 桌面]$  ps -ef | grep ora_ | grep pmon
    [oracle@localhost 桌面]$  ps -ef | grep ora_
    oracle    2950  2597  0 17:05 pts/0    00:00:00 grep ora_
    [oracle@localhost 桌面]$  ps -ef | grep ora_ | grep pmon
    [oracle@localhost 桌面]$ sqlplus / as sysdba;
    
    SQL*Plus: Release 10.2.0.1.0 - Production on Tue Jun 4 17:05:59 2013
    
    Copyright (c) 1982, 2005, Oracle.  All rights reserved.
    
    Connected to an idle instance.
    
    SQL> conn scott/tiger;
    ERROR:
    ORA-01034: ORACLE not available
    ORA-27101: shared memory realm does not exist
    Linux Error: 2: No such file or directory
    
    
    Warning: You are no longer connected to ORACLE.
    SQL> conn / as sysdba;
    Connected to an idle instance.
    SQL> exit;
    Disconnected
    [oracle@localhost 桌面]$  ps -ef | grep ora_
    oracle    2963  2597  0 17:06 pts/0    00:00:00 grep ora_
    [oracle@localhost 桌面]$ startup
    bash: startup: command not found
    [oracle@localhost 桌面]$ sqlplus / as sysdba;
    
    SQL*Plus: Release 10.2.0.1.0 - Production on Tue Jun 4 17:07:01 2013
    
    Copyright (c) 1982, 2005, Oracle.  All rights reserved.
    
    Connected to an idle instance.
    
    SQL> startup
    ORACLE instance started.
    
    Total System Global Area  838860800 bytes
    Fixed Size		    1222192 bytes
    Variable Size		  775948752 bytes
    Database Buffers	   58720256 bytes
    Redo Buffers		    2969600 bytes
    Database mounted.
    Database opened.
    
    SQL> conn scott/tiger;
    Connected.
    SQL> exit;
    Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
    With the Partitioning, OLAP and Data Mining options
    [oracle@localhost 桌面]$  ps -ef | grep ora_
    oracle    2968     1  0 17:07 ?        00:00:00 ora_pmon_orcl
    oracle    2970     1  0 17:07 ?        00:00:00 ora_psp0_orcl
    oracle    2972     1  0 17:07 ?        00:00:00 ora_mman_orcl
    oracle    2974     1  0 17:07 ?        00:00:00 ora_dbw0_orcl
    oracle    2976     1  0 17:07 ?        00:00:00 ora_lgwr_orcl
    oracle    2978     1  0 17:07 ?        00:00:00 ora_ckpt_orcl
    oracle    2980     1  0 17:07 ?        00:00:00 ora_smon_orcl
    oracle    2982     1  0 17:07 ?        00:00:00 ora_reco_orcl
    oracle    2984     1  0 17:07 ?        00:00:00 ora_cjq0_orcl
    oracle    2986     1  1 17:07 ?        00:00:00 ora_mmon_orcl
    oracle    2988     1  0 17:07 ?        00:00:00 ora_mmnl_orcl
    oracle    2990     1  0 17:07 ?        00:00:00 ora_d000_orcl
    oracle    2992     1  0 17:07 ?        00:00:00 ora_s000_orcl
    oracle    2996     1  0 17:07 ?        00:00:00 ora_qmnc_orcl
    oracle    2998     1  2 17:07 ?        00:00:00 ora_j000_orcl
    oracle    3004     1  0 17:07 ?        00:00:00 ora_q000_orcl
    oracle    3006     1  0 17:07 ?        00:00:00 ora_q001_orcl
    oracle    3009  2597  0 17:07 pts/0    00:00:00 grep ora_
    [oracle@localhost 桌面]$  ps -ef | grep ora_ | grep pmon
    oracle    2968     1  0 17:07 ?        00:00:00 ora_pmon_orcl

### 三 总结 ###

1. PMON，进程监控进程，动态注册监听器。

2.作用：清除失败的进程、回滚事务、释放锁、释放其他资源、重启死掉的Dispatchers。

3.Linux下仍然采用ps命令查看。

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