Sybase 12.4.2 - Manual (Page 439)

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C H A P T E R 1 2
Managing System Resources
About this chapter This chapter describes the way Adaptive Server IQ uses memory, disk I/O,
and CPUs, and the relationships among these factors. It also explains how
the DBA can tune performance by adjusting resource usage.
The suggestions in this chapter are generic. You need to adjust them to suit
your hardware and software configuration.
Introduction to performance terms
Performance is the measure of efficiency of a computerized business
application, or of multiple applications running in the same environment.
It is usually measured in response time and throughput.
Response time is the time it takes for a single task to complete. It is
affected by:
• Reducing contention and wait times, particularly disk I/O wait times
• Using faster components
• Reducing the amount of time the resources are needed (this is the
same as increasing concurrency)
Throughput refers to the volume of work completed in a fixed time period.
Throughput is commonly measured in transactions per second (tps), but
can be measured per minute, per hour, per day, and so on.
Designing for performance
Most gains in performance derive from good database design, thorough
query analysis, and appropriate indexing. The largest performance gains
can be realized by establishing a good design and by choosing the correct
indexing strategy.