Oracle architecture and backup (13) bg-pmon

1. What is the PMON process Theprocessmonitorperformsprocessrecoverywhenauserprocessfails. Metadata. PMONalsochecksonthedispatcherprocesses (described

What is a PMON process 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

1. What is a PMON process?

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, process monitoring process (Dynamic register listener)

Purpose:

Clear failed processes

Roll back a transaction

Release lock

Release other resources

Restart the dead Dispatchers

Example 2

Oracle @ localhost desktop] $ ps-ef | grep ora _ | grep pmonoracle 2889 1 0 :01? 00:00:00 ora_pmon_orcl [oracle @ localhost desktop] $ kill-9 2889 [oracle @ localhost desktop] $ ps-ef | grep ora _ | grep pmon [oracle @ localhost desktop] $ ps-ef | grep ora_oracle 2950 2597 0 00:00:00 pts/0 grep ora _ [oracle @ localhost desktop] $ ps-ef | grep ora _ | grep pmon [oracle @ localhost desktop] $ sqlplus/ as sysdba; SQL * Plus: Release 10.2.0.1.0-Production on Tue Jun 4 17:05:59 2013 Copyright (c) 1982,200 5, Oracle. al L rights reserved. connected to an idle instance. SQL> conn scott/tiger; ERROR: ORA-01034: ORACLE not availableORA-27101: shared memory realm does not existLinux Error: 2: No such file or directoryWarning: You are no longer connected to ORACLE. SQL> conn/as sysdba; Connected to an idle instance. SQL> exit; Disconnected [oracle @ localhost desktop] $ ps-ef | grep ora_oracle 2963 2597 0 00:00:00 pts/0 grep Ora _ [oracle @ localhost desktop] $ startupbash: startup: command not found [oracle @ localhost desktop] $ sqlplus/as sysdba; SQL * Plus: release 10.2.0.1.0-Production on Tue Jun 4 17:07:01 2013 Copyright (c) 1982,200 5, Oracle. all rights reserved. connected to an idle instance. SQL> startupORACLE instance started. total System Global Area 838860800 bytesFixed Size 1222192 bytesVariable Size 775948752 bytesDatabase B Uffers 58720256 bytesRedo Buffers 2969600 bytesDatabase mounted. database opened. SQL> conn scott/tiger; Connected. SQL> exit; Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0-ProductionWith the Partitioning, OLAP and Data Mining options [oracle @ localhost desktop] $ ps-ef | grep ora_oracle 2968 1 0 :07? 00:00:00 ora_pmon_orcloracle 2970 1 0? 00:00:00 ora_psp0_orcloracle 2972 1 0? 00:00:00 ora_mman_orcloracle 2974 1 0? 00:00:00 ora_dbw0_orcloracle 2976 1 0? 00:00:00 ora_lgwr_orcloracle 2978 1 0? 00:00:00 ora_ckpt_orcloracle 2980 1 0? 00:00:00 ora_smon_orcloracle 2982 1 0? 00:00:00 ora_reco_orcloracle 2984 1 0? 00:00:00 ora_cjq0_orcloracle 2986 1? 00:00:00 ora_mmon_orcloracle 2988 1 0? 00:00:00 ora_mmnl_orcloracle 2990 1 0? 00:00:00 ora_d000_orcloracle 2992 1 0? 00:00:00 ora_s000_orcloracle 2996 1 0? 00:00:00 ora_qmnc_orcloracle 2998 1 2? 00:00:00 ora_j000_orcloracle 3004 1 0? 00:00:00 ora_q000_orcloracle 3006 1 0? 00:00:00 ora_q0020.orcloracle 3009 2597 0 00:00:00 pts/0 grep ora _ [oracle @ localhost desktop] $ ps-ef | grep ora _ | grep pmonoracle 2968 1 0? 00:00:00 ora_pmon_orcl

Summary

1. PMON, process monitoring process, dynamic register listener.

2. Role: Clear failed processes, roll back transactions, release locks, release other resources, and restart dead Dispatchers.

3. Run the ps command in Linux.

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