RE: How to Monitor Wait Event Average Elapsed Time Using EMCC12c

From: <fmhabash_at_gmail.com>
Date: Wed, 24 Feb 2016 14:25:02 -0500
Message-ID: <56ce0392.679f320a.4c793.53fb_at_mx.google.com>

We know for a fact that if some wait events appear on an Oracle database, it will slow down and users will call. These are the root cause of almost every performance issues I have tackled and this is how we approach Oracle performance tuning anyway.

Database performance degrades if these events appear or have high elapsed times. Events such as mutex/latch contention, severe enqueuer waits, log file syncs exceeding 300 ms and db file sequential reads over 600 ms.

People do not typically examine AWR/ASH reports routinely to see these anomalies and certainly not for proactive purposes. We are only talking a subset of ‘nasty’ events.

There are third party tools that have this feature built it. It utilizes AWR data to construct its monitors.

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Thanks

From: Kellyn Pot'Vin-Gorman
Sent: Wednesday, February 24, 2016 2:09 PM To: fmhabash_at_gmail.com
Cc: Courtney Llamas; Oracle-L Group
Subject: Re: How to Monitor Wait Event Average Elapsed Time Using EMCC12c

The Enterprise Manager product is a self-service product.  There are a ton of features and products that Oracle works very hard to keep as "light" as possible.  The important monitoring features may differ drastically from one customer to another. What may be a top ten for you, even if it were to be disabled, may be far down on the list for another customer, so we've ensured that you have the functionality available to ensure you can monitor almost anything imaginable.

Hope this helps,
Kellyn Pot'Vin-Gorman
Consulting Member of Technical Staff, SCP Oracle

    Kellyn Pot'Vin-Gorman
about.me/dbakevlar  
On Wed, Feb 24, 2016 at 12:02 PM, <fmhabash_at_gmail.com> wrote: Since it is not default, how are you handling scenarios where your database latch/mutex contention goes 2000% at 150 ms proactively?  
Even though possible to do through home-grown scripts, but if adaptive monitors are suited the most for anything, it is for wait event monitoring. Having to engineer such adaptive feature is not something clients are willing to pay for.    
Do you rely on v$system_event/v$session_event?  

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Thanks
 
From: Courtney Llamas
Sent: Wednesday, February 24, 2016 1:36 PM To: fmhabash_at_gmail.com; Kellyn Pot'Vin-Gorman

Cc: Oracle-L Group
Subject: RE: How to Monitor Wait Event Average Elapsed Time Using EMCC12c  
You can see the available metrics in the DB Reference guide - http://docs.oracle.com/cd/E24628_01/em.121/e25160/oracle_database.htm#EMDBM3179.  These correspond to the DB wait event classes http://docs.oracle.com/cd/E11882_01/server.112/e40402/waitevents001.htm#BGGHJGII  
Setting thresholds on each specific wait would be very time consuming and error prone when new versions/waits are introduced.  
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- Courtney

Courtney Llamas | Consulting Member of Technical Staff Phone: +2814108258 | Mobile: +8324720596 Oracle Strategic Customer Program

Oracle
Oracle is committed to developing practices and products that help protect the environment   From: fmhabash_at_gmail.com [mailto:fmhabash_at_gmail.com] Sent: Wednesday, February 24, 2016 12:27 PM To: Kellyn Pot'Vin-Gorman
Cc: Oracle-L Group
Subject: RE: How to Monitor Wait Event Average Elapsed Time Using EMCC12c  
I’m a bit surprised why did Oracle not include such metrics in the default template, even if disabled.  

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Thanks
 
From: Kellyn Pot'Vin-Gorman
Sent: Wednesday, February 24, 2016 1:24 PM To: fmhabash_at_gmail.com
Cc: Oracle-L Group
Subject: Re: How to Monitor Wait Event Average Elapsed Time Using EMCC12c  
By the data you've provided, elapsed time per a specific wait event isn't a default metric, but yes, you could easily create this with a metric extension.  Once you add it to a target, then use that target as the base for a template and then you can use it elsewhere.  
Hope this helps,
Kellyn

    Kellyn Pot'Vin-Gorman
about.me/dbakevlar    
On Wed, Feb 24, 2016 at 11:02 AM, <fmhabash_at_gmail.com> wrote: I had a need to create EM monitors/alerts when a particular wait event average elapsed time exceeds a threshold. Looking at the default template, I see wait classes (by waiter count)  and no wait event metrics.  
Are wait event metrics not available in anywhere in a template? Do I have to create a metric extension for this purpose?  

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http://www.freelists.org/webpage/oracle-l Received on Wed Feb 24 2016 - 20:25:02 CET