Oracle DBA Best Practices

Dennis WilliamsSenior Database AdministratorLifetouch, Inc.

About Me TCOUG member since 1990 8 years only DBA at Lifetouch, Inc. Lawson Software Database

Research Engineer Consultant - Fingerhut Control Data Contact me at

dwilliams@lifetouch.com

Audience Those considering DBA career DBAs who want to improve Those forced to tolerate DBAs

There’s no asset more important than a company’s data. You can’t give that responsibility to someone who doesn’t know how to handle it.

Malcom Fields, CIOHon Industries

Agenda Time - Until lunch is ready Left-brain portion - tech. Issues Right-brain portion - softer issues Database audit form

75,610 DBAs U.S. Bureau of Labor Statistics in

2003 began tracking the IT workforce.

6.46% unemployed There are 797,445 Software

Engineers (5.3% unemployed) DBA supports about 10 developers. 66% DBA growth by 2010

Where do DBAs come from? Schools don’t offer a degree. Developer DB developer System Administrator

DBA is a role Like a policeman or teacher Unstated responsibilities,

expectations Most people don’t know what a

DBA does.

DBA time breakdown 22% Fire Fighting 33% Monitoring 12% Perf. Tuning / Change Mgt. 33% Development Support 0% Planning for growth 0% Backup & Recovery Planning 0% Learning

Koopman

Assignment Keep a personal time log - 1 week Learn your time distribution Target improvements Study time management

Levels of Oracle DBARookie Veteran Expert

TCOUG No time Member,attends reg.

On theboard

Studies Admin.Commands

Concepts Architecture

Manuals No time Readsmanuals

Veryfamiliar

Learning Takesclasses

OCP, books OCM,author,conferences

Onlineforums

No time Lurks, asks Answersquestions

New Oraclefeatures

Uses anyfeature

Wary ofnew feature

Createstests to findproblems

OCP Misconception: you are an expert Multiple choice, so simple

questions Broad, not deep Career benefit - can’t hurt Can help you go deeper in Oracle

Types of DBAs:Development DBA

May carry developer title Develop code ( PL/SQL ) “Hunter” personality (find/fix/forget) Best practices: Code Complete by

McConnell

Production Support DBA Keep it running “shepherd / farmer” personality Where best practices really make a

difference The hero isn’t the DBA that battles

problems through the weekend, but the one that avoided the problem

Application DBA Supports a business critical app. like

Oracle Financials, SAP, Peoplesoft, Lawson

Production support, some dev. Key skill: understands how the app.

Interacts with Oracle Can’t self-study Caution: Vendor doesn’t operate

databases in production

Consultant DBA Fastest way to get expertise Varied work opportunities Understand economic cycles

Backup is Job #1 Ensuring data is never lost Don’t trust an untested backup

configuration Be ready to perform any type of recovery

at any time Communicate vulnerabilities, recovery

times to management Archivelog mode by default Cold or Hot backups, which best fits your

environment

Export: the DBAs friend Enhance recoverability Easy to recover a single table,

avoid full recovery Checks block corruption Teach your developers to request

special exports Validate, no errors, Unix strings

command, last line should be EXIT

Security is Job #2 DBA is responsible for making data

available to authorized users Keeping data inaccessible to

unauthorized Role: policy, implementation Know security options, implications Know how application affects

security, data sensitivity

Making it workDev to Prod

ITIL 3 environments - test/stage/prod Clone DB from backup Developers provide scripts to change

production Simple application login test Always have a backout plan Is this change worth the possible

consequences?

Oracle Performance Tuning - Types SQL Statements - explain plan,

tkprof, 10053 events Application disasters - 10046 trace,

Cary Millsap (TCOUG Hotsos seminar)

Proactive tuning and hanging - STATSPACK, utlestat/utlbstat

Server statistics If you have a performance

problem, either your database is working too hard, or it’s not being allowed to work. - Jonathan Lewis

You must know what your server is doing.

You must know the O.S. Unix Admin. - your best friend

Bind variables Ensure developers use bind

variables Audit v$sql in test to verify In Java, PreparedStatement In .net, CommandText,

CreateParameter, Append Connection pooling

Not your Dad’s Oracle tuning Rules of thumb, ratios to

mathematical foundations Counts to measured times in

microseconds Aggregate by instance to process

details V$ tables are either too

summarized or point-in-time

Goal of tuning What matters to the business user Good chance to sell value End-to-end analysis DBA must prove innocence

Monitoring There is nothing so useless

as doing efficiently that which shouldn’t be done at all - Peter F. Drucker

Use LMT, uniform extents, vs. rebuild

Use autoextend vs. monitoring Email exceptional conditions

Oracle Versions Be not the first by whom the new

are tried, nor yet the last to lay the old aside - Alexander Pope

Good choice saves downtime Support by appl, O.S. Rule of 4’s - 7.3.4, 8.1.7.4, 9.2.0.4 Timing - can I skip versions? Appl. quality requirements What are others saying? Metalink Only change one major component

Oracle Patches Two philosophies:

Only when bug arises Immediately (security)

Vendor testing hierarchy: Version Patch set Individual patch

Oracle Licensing Install defaults to all - know what

costs extra Consider Standard Version Understand the organization

budget mechanisms Knowledgeable if not authorized

Troubleshooting Never worked? Check installation Worked earlier, doesn’t work now?

What changed? Intermittent? (worst kind) How does

it vary? With time, system load, hardware?

From Oracle Networking 101 by Marlene Theriault

Documentation Key: What is essential? Don’t document what can easily be

figured out Keeping up-to-date is the crucial

aspect. Obsolete documentation is

treacherous Self-documenting where possible

Data Modeling O-O Developer: Database is just a

means to persist classes DBA: Good data modeling can

ensure the data is usable across the enterprise

Data architect is a DBA career path Participate in initial design where

your leverage is large Learn data modeling software

Tech. Learning List Application interface methods -

Microsoft, Java, OCBC Server tuning Storage methods and options,

strengths and weaknesses

Effective communication proceeds from shared knowledge

Self-Study When you can’t get experience Be aware of the limits Well-defined area? (books?) Can earn credentials? Area where you can gain significant

knowledge with a reasonable effort? Average experience of competitors is

short Enjoy after doing 10 years?

Know your learning style Left-brain vs. right-brain Four primary learning styles:

Visual (diagrams) Auditory (reading) Tactile (hands-on) Kinesthetic (body)

Your manager’s learning style

People Skills Few people besides a DBA understand

what a DBA does This makes it hard to communicate your

value to the organization People don’t mind paying for what they

value, but resist paying for what they don’t consider valuable

If your manager is a DBA, less people skills are required, but this is career-limiting

Respect Do you respect someone who doesn’t

respect you? The root of much conflict is a mutual

lack of respect Smartness paradox We are the hero of our own movie, we

justify ourselves, never the bad guy Really care about the people you

work with

How to avoid problems Many bad reactions stem from a

lack of warning Emotions play a large role in

decision-making Work hard to warn people ahead of

time of what will be coming Don’t know why? Assume stupidity A DBA appreciates a heads-up,

why shouldn’t others?

When you’re wrong, admit it, quickly Any man worth his salt will

stick up for what he believes right, but it takes a slightly better man to acknowledge instantly and without reservation that he is in error - Andrew Jackson

Stress Feeling no control Constant interruptions DBA syndrome - responsible for

everything, control nothing, nobody understands

You hear yourself saying “nobody appreciates me”

Antidote: study stress control, exercise

visit clients, future changes

That Problem Person Sandwich / Oreo approach by Rachel

Carmichael 1-on-1 outside the office Begin with a complement Make statements addressing the

problem, starting with “I” - “I feel”, “I think”, “what I see is”. Listen

Wrap with team-building “we can work together on this”, “I need your help”

End with a nice complement

Simple Explanations The most valuable people are

those who can understand complex issues and explain them simply to others

Makes other feel good about themselves

Albert Einstein, Steve Hawking, Carl Sagan, Richard Feynman

Database Audit Form Periodically audit each database Checklist for problems Form is terse, so I included a sheet

describing the purpose of each check