Merge pull request #839 from dajiaohuang/docs/fix-adsbdb-cache-ttl

docs: correct ADSBDB cache TTL note

server/providers/aircraft/enrichment.js

@@ -7,8 +7,9 @@ const ADSBDB_MAX_RESPONSE_BYTES = 1024 * 1024;
 /**
  * adsbdb.com enrichment proxy: callsign → route (airline + origin/destination
  * airports) and hex → aircraft type/registration. Free community API — cached
- * aggressively: ONE upstream request per new key ever (404s negative-cached),
+ * aggressively: successes and 404s are kept per key for 24 hours (TTL_MS) and
- * persisted to disk so restarts don't re-hammer it. Adapted from skylight
+ * persisted to disk so restarts don't re-hammer it; other failures are not
+ * cached. Adapted from skylight
  * (MIT) server/src/enrich/routes.ts.
  */
 export function adsbdbProxy() {

src/layers/flights/policy.js

@@ -219,8 +219,8 @@ export const COURSE_SLEW_DT_MAX_SEC = 0.25;
 // adsbdb enrichment (best-effort, fail-silent). Bounded fan-out: max 4
 // concurrent requests, dispatches dripped ≥ENRICH_DISPATCH_GAP_MS apart
 // (≤5/s — adsbdb is a free community API; the dev-server proxy additionally
-// caches per-key on disk forever, negative results included, so repeat
+// caches successful and 404 responses per key for 24 hours, so later sessions
-// sessions never re-hit adsbdb). Each key is requested at most once per
+// may refresh them). Each key is requested at most once per
 // session. Priority jobs (tracked plane, model-eligible planes) jump the
 // queue; the ambient fleet sweep (below) fills the back at poll cadence.
 // ---------------------------------------------------------------------------
@@ -243,7 +243,7 @@ export const ENRICH_DISPATCH_GAP_MS = 200;
 //     of drip, so the backlog can't outgrow a poll and re-sorts fresh), and
 //   - a ROLLING token-bucket budget (below) bounding the sustained ambient
 //     request rate (repeat sessions resolve instantly from the proxy's
-//     permanent disk cache).
+//     24-hour disk cache).
 // Fail-silent by contract: the sweep never throws into the poll loop, never
 // blocks rendering, and never touches tracking state. When a type answer
 // lands, _requestTypeEnrichment's callback swaps the billboard glyph + scale
@@ -257,7 +257,7 @@ export const ENRICH_DISPATCH_GAP_MS = 200;
 // ENRICH_AMBIENT_REFILL_TOKENS every ENRICH_AMBIENT_REFILL_WINDOW_MS, clamped
 // at the ceiling (no banking beyond one bucket). Numbers: 150 / 5 min sustains
 // 0.5 req/s worst case — an order of magnitude under the 5/s drip that (with
-// the 4-concurrent limit + the proxy's permanent disk cache) is the REAL
+// the 4-concurrent limit + the proxy's 24-hour disk cache) is the REAL
 // politeness bound on adsbdb; the 300 ceiling preserves the old first-look
 // burst so a fresh region still classifies quickly.
 /** Bucket ceiling: max ambient tokens held at once (= the initial burst). */