Fix false 100% burn rates for low-traffic SLO endpoints#167
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Replace clamp_min + bool multiplication guard with direct division and per-window 'and total > 0' guard. The previous approach produced false 100% error ratios during traffic transitions because: 1. clamp_min(total, 0.001) computed 1-(0/0.001)=1 when total was 0 2. The bool guard used the 5m total which could briefly be >0 during traffic pulses, letting the false 1 through to the longer windows The new approach uses each window's own total for the guard and returns no data (instead of 1) when there's no traffic in that specific window. This matches the pattern already working correctly for the 5m rules. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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kevwilliams
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Mar 27, 2026
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Summary
Fixes multi-window SLO error ratio recording rules that were producing false 100% values for low-traffic endpoints (metadata, audit queries, activity queries).
Problem
The 1h, 6h, and 3d error ratio rules used
clamp_min(total, 0.001)to avoid division by zero, combined with a* (rate5m > bool 0)guard. During brief traffic pulses, the guard opened momentarily while the total was still near-zero, producing1 - (0/0.001) = 1(100% error ratio). This caused the burn rate dashboard to show false spikes.Fix
Replace
clamp_min+boolmultiplication with direct division and per-windowand total > 0guards — the same pattern already working correctly for the 5m rules. Each window now uses its own total for the guard instead of referencing the 5m total.Test plan
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