p95
Trips when the 95th percentile (the "slowest 5%") exceeds a threshold.
How it works
Evaluates tail distribution by isolating the slowest 5% of requests. This ensures that high-volume fast requests do not mask significant latency issues affecting a minority of users.
When to use
- Monitoring user-facing latency where worst-case experience is the priority.
- Detecting performance issues affecting specific request subsets.
- Enforcing performance SLAs.
When not to use
- Very small sample sizes where percentiles are mathematically unstable.
- Non-latency metrics where averages are more representative of total cost.
State explanations
closed
The slowest 5% of requests are within acceptable bounds.
half open
Confirming the worst-case performance has stabilized.
open
Tail latency is unacceptably high, affecting user experience.