Databases Reference
In-Depth Information
What are my performance requirements?
What response times do your users expect, and how much of that time can you give
them? Will you measure performance in terms of average response time, maximum
response time, response time at peak load, total throughput, or average load?
What are my security requirements?
Will the application, the operating system, or the Oracle Database (or some com‐
bination of these) enforce security? Do I need to implement this security in my
design or with additional security options for the Oracle Database? These options
are described in
Chapter 6
.
The Value of Estimating
Even if you are unsure of things such as sizing and usage details, take your best guess
as to initial values and growth rates and document these estimates. As the database
evolves, you can compare your initial estimates with emerging information to react and
plan more effectively. For example, suppose you estimate that a certain table will be 500
GB in size initially and will grow at 300 GB per year, but when you are up and running
you discover that the table is actually 300 GB, and six months into production you
discover that it has grown to 800 GB. You can now revise your plans to reflect the higher
growth rate and thereby avoid space problems. Comparing production measures of
database size, growth, and usage patterns with your initial estimates will provide val‐
uable insights to help you avoid problems as you move forward. In this way, documented
guesses at an early stage are useful later on.
The same is true for key requirements such as availability and performance. If the exact
requirements are not clear, make some assumptions and document them. These core
requirements will heavily influence the decisions you make regarding redundancy and
capacity. As the system evolves and these requirements become clearer, the history of
these key decision criteria will be crucial in understanding the choices that you made
and will make in the future.
The Automatic Workload Repository (AWR), first available in Oracle Database 10
g
,
maintains a history of workload and performance measurements, which are used by
the Automatic Database Diagnostic Monitor (ADDM) to spot performance anomalies.
You can also use AWR to track ongoing changes in workload.
Tools for Creating Databases
Traditionally, there have been two basic ways to create an Oracle Database:
• Use the graphical installer tool
• Run character-mode scripts
