Understanding Apdex
Apdex (Application Performance Index) is a standardized method for measuring and reporting application performance.
It converts many measurements into one simple number on a uniform scale of 0 to 1.
Key Concepts:
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Satisfied Requests (S): Requests that complete in less than or equal to T seconds,
where T is the Satisfied Threshold. These are requests that met the performance goal.
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Tolerating Requests (T): Requests that complete in greater than T seconds but less than or equal to 4T seconds.
These requests didn't meet the goal, but users are still reasonably tolerant of the delay.
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Frustrated Requests (F): Requests that take longer than 4T seconds to complete.
These are considered unacceptable performance and likely to drive users away.
Apdex Score Calculation:
The Apdex score is calculated as: (Satisfied Count + (Tolerating Count / 2)) / Total Samples
This results in a score between 0 (no satisfaction) and 1 (perfect satisfaction).
Interpreting the Score:
- 0.94 - 1.00: Excellent
- 0.85 - 0.93: Good
- 0.70 - 0.84: Fair
- 0.50 - 0.69: Poor
- 0.00 - 0.49: Unacceptable