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Primary Note: Troubleshooting Oracle Background Processes (Doc ID 1509616.1)

Last updated on JANUARY 29, 2022

Applies to:

Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version and later
Oracle Database - Standard Edition - Version to [Release 11.2]
Oracle Database - Standard Edition - Version to [Release 11.1]
Information in this document applies to any platform.


This document is intended to assist Database Administrators resolve issues encountered involving Oracle Background Processes. It mainly applies to a single instance environment and looks at a basic typical database configuration.

Troubleshooting Steps

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In this Document
Troubleshooting Steps
 Issues Involving Oracle Background Processes
 ORA- errors related to Background Processes
 ORA-443 background process did not start
 ORA-444 background process failed while starting
 ORA-445 background process did not start after seconds
 ORA-446 background process started when not expected
 ORA-447 fatal error in background process
 ORA-448 normal completion of background process
 ORA-449 background process unexpectedly terminated with error
 ORA-450 background process '%s' did not start
 Generic issues not related to a specific background process
 CJQ0 / Jnnn ( Job Queue Coordinator Process / Job Queue Secondary Processes )
 Issues Specific to CJQ0 / Jnnn
 CKPT ( Checkpoint Process )
 Issues Specific to CKPT
 DBWn ( Database Writer Process )
 Issues Specific to DBWn
 EMNC /Ennn ( EMON Coordinator Process / EMON Secondary Process )
 Issues Specific to EMNC / Ennn
 LGWR ( Log Writer Process )
 Issues Specific to LGWR
 MMON / Mnnn ( Manageability Monitor Process / MMON Secondary Process )
 Issues Specific to MMON / Mnnn
 PMON ( Process Monitor )
 Issues Specific to PMON
 QMNC / QMNn ( AQ Coordinator Process / AQ Server Class Process )
 Issues Specific to QMNC / QMNn
 RECO ( Recoverer Process )
 Issues Specific to RECO
 SMON ( System Monitor Process )
 Issues Specific to SMON
 VKTM ( Virtual Keeper of Time Process )
 Issues Specific to VKTM
 Wnnn ( Space Management Secondary Process )
 Issues Specific to Wnnn
 Helpful Articles on Background Processes
 Further Diagnostics

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