FA-73802 / Rate limiter algorithms / Member archive

Combined per-second and per-minute fixed windows: minute counter resets every second · case 02

The per-minute limit is never reached because it is cleared whenever a new second starts.

Member previewVariant 2 · 3 implementations · 6 checks per implementation

Case contract

Input {per_second, per_minute, requests [t_ms]} with nondecreasing t. Second windows are t div 1000 and minute windows t div 60000, each resetting its own counter only when its own window changes. The second limit is checked first ("deny-second"), then the minute limit ("deny-minute"); only admitted requests are counted, in both windows. Return [decisions, second count, minute count].

Why this case matters

Public APIs commonly publish several simultaneous limits; coupling their resets or charging denied requests to one of them breaks the published contract.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
minute budget spans seconds	`[["allow", "allow", "allow", "allow", "allow", "allow", "allow", "allow"], 1, 1]`	`[["allow", "allow", "allow", "allow", "allow", "deny-minute", "deny-minute", "deny-minute"], 0, 5]`	Failed

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