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Troubleshooting: High CPU Utilization (Doc ID 164768.1)

Last updated on AUGUST 04, 2018

Applies to:

Oracle Database - Personal Edition - Version 7.1.4.0 and later
Oracle Database - Standard Edition - Version 7.0.16.0 and later
Oracle Database - Enterprise Edition - Version 7.0.16.0 and later
Generic UNIX
Generic Windows

Purpose

The purpose of this document is to help in diagnosing the reason for Oracle related processes consuming high CPU

Troubleshooting Steps

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In this Document
Purpose
Troubleshooting Steps
 Prevention of High CPU utilization
 Managing High CPU Usage with Resource Manager
 What to look for when multiple processes are using the CPU intensively
 What to look for when one process is using the CPU intensively
 Which process is hogging the CPU?
 Background Processes
 PMON
 SMON
 LGWR & DBWR
 Job processes (CJQ0, Jn, SNPn)
 Advanced Queuing (AQ, QMN)
 Parallel Query (Pnn)
 Oracle (User) processes
 OS Processes and defunct processes
 Finding High CPU Utilization processes on Windows
 Finding High CPU Utilization processes on Unix
 Find Top Activity and Top CPU Session Using ASH Tab From Grid Control
References

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