cache: Short TTL negative cache for 404/410 depot objects #40

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opened 2026-09-04 18:51:03 +00:00 by eva · 0 comments

eva commented

2026-09-04 18:51:03 +00:00

Owner

Problem

A 404/410 depot chunk gets re-fetched forever on every miss, so ops see “caching” while Steam gets hammered for dead paths.

Why

Stop hammering upstream for definitive gone objects.

Scope

Short TTL negative entry for definitive upstream failures (404/410)
One /metrics counter
Same cache; no second stack

Acceptance

Repeated miss for a gone object does not re-hit upstream within TTL (test)
Metrics expose negative-cache hits
Document TTL / behavior briefly

Out of scope

#31 HEAD; caching arbitrary 5xx as negative without care

Size: S. From Forge Meeting (Pike).

## Problem A 404/410 depot chunk gets re-fetched forever on every miss, so ops see “caching” while Steam gets hammered for dead paths. ## Why Stop hammering upstream for definitive gone objects. ## Scope - Short TTL negative entry for definitive upstream failures (404/410) - One `/metrics` counter - Same cache; no second stack ## Acceptance - Repeated miss for a gone object does not re-hit upstream within TTL (test) - Metrics expose negative-cache hits - Document TTL / behavior briefly ## Out of scope - #31 HEAD; caching arbitrary 5xx as negative without care Size: S. From Forge Meeting (Pike).