Question: I'm a scientist by training
and my BS degree in electrical engineering has not prepared me well for the
crazy world of Oracle performance tuning. I was taught to carefully
collect and analyze data,but in an Oracle emergency I must make decisions based
on incomplete information. My decisions go from being "certain" to being
"probabilistic", and as a scientist, I find it very uncomfortable. How do
Oracle DBA's learn to make decisions with incomplete data?
Answer: This is a very common question, and
one that deserves a thoughtful answer.
First, Oracle tuning is never fully quantifiable, so you
need to develop an "MBA Mindset" towards problem solving:
-
The very act of instrumenting Oracle can cause a
performance slowdown! See here for an example
instrumenting
PL/SQL. Also see how you can instrument end-to-end response time
in SQL*Forms, but with measurable overhead.
-
Some components of Oracle are non-quantifiable.
The Oracle CBO cannot, by definition, always have current metadata.
-
Tuning a active database is like tuning a car while
it's flying down the freeway at 80 mph! Things happen very quickly, a
reason that Oracle 11g has adopted a holistic approach, where you tune
Oracle with real-world workloads to optimize with proven broad-brush
Silver
Bullet techniques.
The effective DBA must apply the techniques that are taught
in all AACSB accredited business schools. The business schools know that
almost all business problems are semi-structured and that an effective manager
must make decisions with limited data and compute probabilities on the fly.
You will see this bias towards problem solving with probabilities in the
GMAT exam,
and it's a critical skill.
With practice, an Oracle DBA can quickly learn how to
determine probabilities on-the-fly. In 90 seconds, solve any problem, and be
accurate to within +- 10% For example, most people are surprised to find
that they can determine the total number of pizza parlors in the Chicago
metropolitan area with great accuracy.
These SWAG (a "Scientific Wild-A**ed Guess") techniques are
now being taught in all AACSB business schools.
This article notes
that MBA are only given 25 minutes to solve these semi-structured problems:
1. Why are manhole covers round?
2. Why are soda cans tapered at the top and bottom?
3. You are working for the manager of a plastics company. The division is
unprofitable and is known for poor customer service What would you do?
4. How many barbers are there in Chicago? (McKinsey)
5. How many golf balls does it take to fill an Olympic sized swimming pool?
(Booz Allen & Hamilton)
6. You are in a boat in a lake holding a rock. You drop the rock into the
lake. Will the water level of the lake rise?
7. You and your neighbor, who aren't necessarily friends, are planning lawn
sales for the same day. You are both planning to sell the same type of used
appliance in the same condition. You plan to price the appliance at $100.
Your neighbor plans to sell his for $40. What do you do? (Boston Consulting
Group)
8. You are in a room with three light switches. Each one controls one
lightbulb in the adjacent room. You need to discover which switch controls
which bulb. You may flick only two switches, and you may enter the adjacent
room with the lightbulbs only once. What do you do? (Boston Consulting
Group)
9. How long would it take to move Mount Fuji (Booz Allen & Hamilton)
In sum, I would recommend that you supplement your BSEE
with an MBA, but be careful to only choose an AACSB accredited MBA school, an
avoid
diploma mill MBA's.
 |
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might enjoy my book "Oracle
Tuning: The Definitive Reference", with 950 pages of tuning tips and
scripts.
You can buy it direct from the publisher for 30%-off and get instant
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and include the URL for the page.
