Performance tuning as a practice

Work on improving database performance has its own terminology, just like any other field. Here are some terms or phrases that will be used throughout the book:

• Bottleneck or limiting factor: Both of these terms will be used to refer to the current limitation that is keeping the performance from getting better.
• Benchmarking: Running a test to determine how fast a particular operation can run. This is often done to figure out where the bottleneck of a program or system is.
• Profiling: Monitoring what parts of a program are using the most resources when running a difficult operation such as a benchmark. This is typically to help prove where the bottleneck is, and whether it's been removed as expected after a change. Profiling a database application usually starts with monitoring tools such as vmstat and iostat. Popular profiling tools at the code level include gprof, oprofile, and dtrace.

One of the interesting principles of performance tuning work...