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Kpa-clawbot
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## Cache Invalidation Tuning — 7% → 50-80% Hit Rate Fixes #720 ### Problem Server-side cache hit rate was 7% (48 hits / 631 misses over 4.7 days). Root causes from the [cache audit report](https://github.com/Kpa-clawbot/CoreScope/issues/720): 1. **`invalidationDebounce` config value (30s) was dead code** — never wired to `invCooldown` 2. **`invCooldown` hardcoded to 10s** — with continuous ingest, caches cleared every 10s regardless of their 1800s TTLs 3. **`collisionCache` cleared on every `hasNewTransmissions`** — hash collisions are structural (depend on node count), not per-packet ### Changes | Change | File | Impact | |--------|------|--------| | Wire `invalidationDebounce` from config → `invCooldown` | `store.go` | Config actually works now | | Default `invCooldown` 10s → 300s (5 min) | `store.go` | 30x longer cache survival | | Add `hasNewNodes` flag to `cacheInvalidation` | `store.go` | Finer-grained invalidation | | `collisionCache` only clears on `hasNewNodes` | `store.go` | O(n²) collision computation survives its 1hr TTL | | `addToByNode` returns new-node indicator | `store.go` | Zero-cost detection during indexing | | `indexByNode` returns new-node indicator | `store.go` | Propagates to ingest path | | Ingest tracks and passes `hasNewNodes` | `store.go` | End-to-end wiring | ### Tests Added | Test | What it verifies | |------|-----------------| | `TestInvCooldownFromConfig` | Config value wired to `invCooldown`; default is 300s | | `TestCollisionCacheNotClearedByTransmissions` | `hasNewTransmissions` alone does NOT clear `collisionCache` | | `TestCollisionCacheClearedByNewNodes` | `hasNewNodes` DOES clear `collisionCache` | | `TestCacheSurvivesMultipleIngestCyclesWithinCooldown` | 5 rapid ingest cycles don't clear any caches during cooldown | | `TestNewNodesAccumulatedDuringCooldown` | `hasNewNodes` accumulated in `pendingInv` and applied after cooldown | | `BenchmarkAnalyticsLatencyCacheHitVsMiss` | 100% hit rate with rate-limited invalidation | All 200+ existing tests pass. Both benchmarks show 100% hit rate. ### Performance Justification - **Before:** Effective cache lifetime = `min(TTL, invCooldown)` = 10s. With analytics viewed ~once/few minutes, P(hit) ≈ 7% - **After:** Effective cache lifetime = `min(TTL, 300s)` = 300s for most caches, 3600s for `collisionCache`. Expected hit rate 50-80% - **Complexity:** All changes are O(1) — `addToByNode` already checked `nodeHashes[pubkey] == nil`, we just return the result - **Benchmark proof:** `BenchmarkAnalyticsLatencyCacheHitVsMiss` → 100% hit rate, 269ns/op Co-authored-by: you <you@example.com>