Oracle DBA Best Practices

Dennis Williams

Senior Database Administrator

Lifetouch, 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

Theres no asset more important than a companys data. You cant give that responsibility to

someone who doesnt know how to handle it.

Malcom Fields, CIO

Hon 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 dont offer a degree.

Developer DB developer

System Administrator

DBA is a role Like a policeman or teacher

Unstated responsibilities,

expectations

Most people dont 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 DBA

Rookie 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 - cant 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 isnt 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

Cant self-study

Caution: Vendor doesnt 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

Dont 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 work Dev 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 its 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 Dads 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

shouldnt 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 4s - 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, doesnt 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?

Dont 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 cant 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 managers 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 dont mind paying for what they value, but resist paying for

what they dont consider valuable

If your manager is a DBA, less

people skills are required, but this

is career-limiting

Respect

Do you respect someone who

doesnt 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

Dont know why? Assume stupidity

A DBA appreciates a heads-up,

why shouldnt others?

When youre 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