cpu time event

8/10/2019 Cpu Time Event

1/4

"Oracle DBA tips, scripts and errormessage solutions"

:

- Home -

- Articles -

- Oracle DBA Jobs -

Enter Search Terms search

6Navigate to ...

Home> Scripts> Database Tuning> CPU Time in Top 5 Timed Events on Statspack/AWR Report

CPU Time in Top 5 Timed Events on Statspack/AWR Report

By Robert Jackson| 0 Comments

When I first take a look at a statspack or Automatic Workload Repository (AWR) report, and there have been no reported performance problems, I home inon the Top 5 Timed Events section toward the top of the AWR report. It is from here that you are able to get clues as to which direction you should go in, andtherefore what areas of the report you should look at next.

Top 5 Timed Events

The Top 5 Timed Events section within the statspack/AWR report, gives an overview of the 5 largest wait events across your database instance. It iscommon to see among the top 5 timed events, the CPU Time wait event. Here is the output from an example system:

Top 5 Timed Events

~~~~~~~~~~~~~~~~~~

Avg %DB

Event Wait Class Waits Time(s) Time(ms) Time--------------------------- ----------- --------- ------------ --------- --------

CPU time 134,571.20 55.99

db file sequential read User I/O 6,798,700 39,003.81 5.74 16.23

log file sync Commit 8,854,354 16,754.67 1.89 6.97

log file parallel write System I/O 5,183,339 4,631.02 0.89 1.93

SQL*Net message from dblink Network 3,098,485 4,390.32 1.42 1.83

A lot of people interpret this event as a wait event, in that the database instance was waiting for 721 seconds out of the statspack report period on CPU. In away this is true, because it means that the database has spent 721 seconds worth of the available CPU time on the box processing during this period.However, you have to take into consideration the total amount of CPU time available to you.

CPU Top Timed Event? No Problem

For example, you have an 8 CPU server and you want to know how many CPU seconds you have available to you per hour. That works out at (60 seconds *60 minutes) * 8 cores = 28,800 CPU seconds. So, unless you use more than 28,800 CPU seconds within the hour, you are under your 100% CPU limit.There will always be waits on the CPU within a system, probably more so if you have a larger cache and therefore dont have to retrieve the data from disk asmuch. Just remember that it is not necessarily a problem unless you are at 85% or more of available CPU.

An Ideal World

In an ideal world the top timed event would be the CPU event and that would be optimal. Thats assuming that your database, code and processes were asefficient as they possibly could be. The reason for this? There always has to be a wait event to process and return data to a user, there is no escaping thatfact. Out of all of them, such as disk I/O, contention, locking, etc, CPU is the fastest and most efficient event to be waiting for.

Other Wait Events in Top 5 Timed Events

If you see the control file parallel write wait event in your top 5 timed events in your database, you can read my article control file parallel write.

You might find that the numbers on your AWR report look completely wrong, and the percentage figures dont add up to 100% when they should do. YourAWR Report Shows High % and Wait Timesthen read the article I have written about that when running on a Windows server.

Like it, share it...

Category: Database Tuning

Share

Page 1 of 4CPU Time in Top 5 Timed Events Section of AWR or STATSPACK Report

12.06.2013http://www.ora00600.com/wordpress/scripts/databasetuning/cpu-time-in-top-5-timed-eve ...


2/4

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

Name *

Email *

Website

Comment

55

66

Post Comment

Content blocked

While tryingto retrievethe URL:

http://googleads.g.doubleclick.net/pagead/ads? li2F&dt=1371047304361&bpp=16&shv=r201306 l l _ i-16018&ady=1470&biw=1660&bih=892&oid=3 l l l ievents-on-statspackawr-report%252F%26ei%3

The contentis blockeddue to thefollowingcondition:

The URL you have requested is blocked by a bla li i i i l

il i i

Share




3/4

Name:

Email:

Send Free Report!

**CHECK JUNK EMAIL FOLDER**

We will never sell your details

Most Popular Posts

User Privileges and Oracle RolesORA-04021: timeout occurred while waiting to lock objectOracle 10g to 11g Upgrade GuideORA-29278Monitor Oracle UNDOMonitoring TEMP Space Usage in OracleOracle RMAN Backup & Recovery

Pages

Welcome to ORA00600.com

Information

Become an Oracle DBA ReportContact ORA00600.comFAQs

Oracle DBA Directory of Articles Oracle DBA Jobs

Content blocked

While tryingto retrievethe URL:

http://googleads.g.doubleclick.net/page li2F&dt=1371047304533&bpp=16&shv=r l _ l l-15383&ady=253&biw=1660&bih=892& i l l l i252F%26ei%3D-VS4Udr9E8iHtQbz6YGQ l

The contentis blockeddue to thefollowingcondition:

The URL you have requested is blocked l li i i i l

Your cacheadministratoris:

[email protected]

Astaro Security Gat

Share




4/4

Privacy Policy

Recent Posts

ORA-16014 No Available DestinationsOracle SQL

Quick Links

Log inEntries RSSComments RSS

WordPress.org

ORA00600

2013 ORA00600. All rights reserved.

Share


12 06 2013http://www ora00600 com/wordpress/scripts/databasetuning/cpu time in top 5 timed eve

cpu time event

Documents