P99 · OpenResty Official Blog

P99

OpenResty XRay Aug 28, 2026

OpenResty XRay Updated Aug 28, 2026 17 mins read

P99 Latency: Why Averages Lie, and How to Diagnose the Slowest 1%

openresty-xray p99 latency performance flame-graph

What is P99 latency?
P50 vs P95 vs P99: what each percentile tells you
Why average latency lies
Why is P99 latency high? A root-cause spectrum
How to diagnose high P99 latency
How to reduce P99 latency: fix what you found
Summary
Frequently Asked Questions

What is P99 latency?
P50 vs P95 vs P99: what each percentile tells you
Why average latency lies
Why is P99 latency high? A root-cause spectrum
How to diagnose high P99 latency
How to reduce P99 latency: fix what you found
Summary
Frequently Asked Questions

OpenResty XRay Aug 28, 2026

OpenResty XRay Updated Aug 28, 2026 9 mins read

How We Pinpointed a 244ms Latency Spike in a 500k QPS OpenResty Gateway

openresty-xray qps p99 cpu

Latency Spikes and CPU Waste Hidden Beneath Healthy Averages
Troubleshooting OpenResty Latency Without Code Changes or Restarts
The Results: Latency Spikes Eliminated, 30% Lower CPU Usage
Frequently Asked Questions

Latency Spikes and CPU Waste Hidden Beneath Healthy Averages
Troubleshooting OpenResty Latency Without Code Changes or Restarts
The Results: Latency Spikes Eliminated, 30% Lower CPU Usage
Frequently Asked Questions

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