Oregon and Southern Washington Oracle User Group

Oregon and Southern Washington Oracle User Group

Tuesday, September 18, 2018    REGISTER

Providence/St. Vincents on the WEST SIDE in the Sout

her Auditorium.   Parking is free

Next Meeting:  Tuesday,  November 13,  2018

Oregon and Southern Washington Oracle User Group

Tuesday, September 18, 2018
Congratulations to all participants on a successful

Jared Still
Oak Table Network
Oracle ACE

ASM Internals

Carlos Sierra
Oracle ACE Director, emeritus

Slides:   Reducing Plan Flips
Reducing Plan Flips on 12c multi-tenant: a real-life case study

Reducing CPU spikes on 12c multi-tenant: real-life tips and shared toolhttp://events.constantcontact.com/register/event?llr=tr5fxh8ab&oeidk=a07ef9oxf8z22e2d5afDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlDirections.htmlHome_files/Reducing%20Plan%20Flips.pdfshapeimage_1_link_0shapeimage_1_link_1shapeimage_1_link_2shapeimage_1_link_3shapeimage_1_link_4shapeimage_1_link_5shapeimage_1_link_6shapeimage_1_link_7shapeimage_1_link_8shapeimage_1_link_9shapeimage_1_link_10shapeimage_1_link_11shapeimage_1_link_12shapeimage_1_link_13
MEETING DETAILSDirections.html
PREVIOUS MEETINGSPrevious_Meetings.html
PRESENTATION SLIDESPresentation_Slides.html

Board of Directors

Jon Wasserman

Gary Fox

Don Bateson

Ken Knowles

Clay Jackson

Fahd Saeed

Arlene Gelbolingo

Souvonnah Ramsey

David Portin

Julia Shozen, at-large (Japan actually)


Shibin Li

Cheri Mosbrucker

Ping Zhao

Technology Advisory Board

Maria Colgan

Biju Thomas

Jared Still

Schedule of Events

10:30  Sign-in ,  Continental Breakfast


Professional Business

11:15  Carlos Sierra     

Reducing Plan Flips on 12c multi-tenant: a real-life case study 

12:15  Lunch

1:00   Jared Still

ASM Internals - What you need to know

2:10   Coffee Break

2:25   Carlos Sierra

Reducing CPU spikes on 12c multi-tenant: real-life tips and shared tools      



Presentation Details

Carlos Sierra

Reducing Plan Flips on 12c multi-tenant: a real-life case study

For DBAs, a "plan flip" is when the Cost-based Optimizer (CBO) computes an Execution Plan that performs poorly, compared to prior plans. There are several reasons why plans flip. Mitigation is achieved addressing root cause, but sometimes that process is complex and lengthy. On this sessions we present how we can reduce the amount of plan flips, by enhancing SQL Plan Management (SPM) with a clever algorithm that learns about historical performance of your SQL before implementing a target SQL Plan Baseline (SPB). We also explain how to automate such algorithm to monitor and react to the effects of plan flips, or event to performance regressions while still using the same Execution Plan.

This session is for DBAs, Application Developers, and Managers, responsible for transaction-oriented applications (OLTP). It offers a better understanding of sudden changes on Execution Plans, and how we can prevent performance surprises associated to such changes. Its content is focused on 12c and higer versions of Oracle, but also applicable to 11g.

Jared Still

## ASM Internals - What you need to know

Oracle's ASM storage software is often viewed as a bit of a black box. Typically a DBA creates disk groups, adds tablespaces and disks as needed and forgets about it. Just as a DBA should know how the database works, the astute DBA should have a knowledge of how ASM really works.

A knowledgeable DBA should be able to explain how ASM replicates data, and how this is different than RAID technology. Failgroups are an integral part of ASM, so understanding how they work is critical to understanding ASM.  Allocation units, extents and more will be considered in a discussion of how ASM works.

Many DBA's leave all of the Hardware configuration to System Administrators.  As with DBA's, the quality of System Administrator's work and understanding of the systems vary with the individual.  Dedicated DBA's attending Collaborate 2018 will want to know some basic configuration items to verify before proceeding with ASM installations.  Among topics to be covered will be Disk Partitioning and Sector Alignment.

Troubleshooting and extreme recovery methods will be considered as well. If you do not already know the risks when the value of Usable_file_MB is a negative value, or how you may extract Oracle datafiles directly from ASM disks, then this presentation is for you.

Whether your databases are on premise or in the cloud, if you are using ASM you need to know how it works.

This presentation will show you how ASM works.

How does ASM storage work?  Is it RAID?

What is an Allocation Unit?

Are there utilities to help the DBA diagnose disk and disk group issues?

What is the difference between External and Normal Redundancy?

How do failgroups work?

How do I know which to use?

Should ASM Disks be partitioned?

What is sector alignment, and why should I care?

In the event of failure. can files be retrieved from ASM disks without using ASM?

Carlos Sierra

Reducing CPU spikes on 12c multi-tenant: real-life tips and shared tools

CPU spikes on a database usually trigger some alert, to which a DBA is expected to take some immediate action. A system that gets CPU oversubscription has an impact on latency and throughput, affecting all tenants. The challenge for a DBA in such cases is: determine what causes the CPU spike, then address the root cause. Sometimes the CPU consumption grows slowly over time, and sometimes quite fast. Common causes include "plan flips", repeating jobs, larger datasets, and on 12c multi-tenant, sudden increased load on a pluggable database (PDB) that may impact other tenants if not addressed.

On this session we present real-life tips on how to address common CPU spikes on 12c multi-tenant. We also share some free tools for DBAs to adapt and use. The target audience is: DBAs responsible of databases where SLAs on latency and throughput are critical. It is also educational for Developers and Managers that want to increase their understanding of the database.


Special thanks to Liron, Jared, and Clay for outstanding presentations in September 2017

Visit Liron Amitzi’s commentary summarizing the event

VIew presentation slides:

Liron Amitzi

Presentation Code Examples coming soon

Basic Datatypes - Deep Understanding

Understanding Query Optimizer Complexity

View presentation slides:

Jared Still

Pre-Meeting Revision:  Free-Oracle-Performance-tools

Download Final Meeting Version:  http://bit.ly/free-oracle-tools

What to Consider When Moving Your Oracle Database to the Cloud

May 2017 meeting:

Presentation Slides are now available for Download

Oracle 12c New Features

E-Business DBA Diary

Biju Thomas, OneNeck Solutions


Events in Oregon and Washington

Events Worldwide

Last Updated: August 12,  2018

Copyright Oregon and Southern Washington Oracle User Group and it’s owners and presenters for their content.