DBA Best Practices

1. Oracle DBA Best
Practices
Dennis Williams
Senior Database Administrator
Lifetouch, Inc.

2. 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

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

4. 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, CIO
Hon Industries

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

6. 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

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

8. DBA is a role
 Like a policeman or teacher
 Unstated responsibilities,
expectations
 Most people don’t know what a
DBA does.

9. 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

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

11. Levels of Oracle DBA
Rookie Veteran Expert
TCOUG No time Member,
attends reg.
On the
board
Studies Admin.
Commands
Concepts Architecture
Manuals No time Reads
manuals
Very
familiar
Learning Takes
classes
OCP, books OCM,
author,
conferences
Online
forums
No time Lurks, asks Answers
questions
New Oracle
features
Uses any
feature
Wary of
new feature
Creates
tests to find
problems

12. 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

13. Types of DBAs:
Development DBA
 May carry developer title
 Develop code ( PL/SQL )
 “Hunter” personality (find/fix/forget)
 Best practices: Code Complete by
McConnell

14. 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

15. 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

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

17. 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

18. 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

19. 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

20. 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?

21. 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

22. 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

23. Bind variables
 Ensure developers use bind
variables
 Audit v$sql in test to verify
 In Java, PreparedStatement
 In .net, CommandText,
CreateParameter, Append
 Connection pooling

24. 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

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

26. 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

27. 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

28. Oracle Patches
 Two philosophies:
 Only when bug arises
 Immediately (security)
 Vendor testing hierarchy:
 Version
 Patch set
 Individual patch

29. Oracle Licensing
 Install defaults to all - know what
costs extra
 Consider Standard Version
 Understand the organization
budget mechanisms
 Knowledgeable if not authorized

30. 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

31. 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

32. 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

33. Tech. Learning List
 Application interface methods -
Microsoft, Java, OCBC
 Server tuning
 Storage methods and options,
strengths and weaknesses
 Effective communication proceeds
from shared knowledge

34. 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?

35. 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

36. 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

37. 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

38. 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?

39. 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

40. 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

41. 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

42. 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

43. Database Audit Form
 Periodically audit each database
 Checklist for problems
 Form is terse, so I included a sheet
describing the purpose of each
check