INNER CODE UNIT · TypeScript

ftsProbed

harvard-edge/cs249r_book · interviews/staffml-vault-worker/src/index.ts:86

    ftsProbed = undefined;   // Chip R7-M-5: FTS5 presence can change across releases
    // Chip R7-L-7: don't null manifestMemo — 60s TTL handles rollover, and
    // nulling mid-write caused concurrent-request stampedes on D1.
  }
  lastSeenRelease = releaseId;
}

// Gemini R5-H-1: module-level manifest memo (60s TTL). Before this,
// getManifest hit D1 on every request — including cache-hit requests —
// which silently blew the §10.4 "~5 D1 reads/session" cost target.
let manifestMemo: { manifest: Manifest; at: number } | null = null;
const MANIFEST_TTL_MS = 60_000;

async function getManifest(env: Env): Promise<Manifest> {
  const now = Date.now();
  if (manifestMemo && now - manifestMemo.at < MANIFEST_TTL_MS) {
    return manifestMemo.manifest;
  }

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