Files
HealthLog/src
Marc-André Bombeck 6b7b8a7fdf perf(analytics): default slice delegates to slim rollup-tier reader (v1.4.49.1)
v1.4.49 shipped the slim-slice cold-fallback fix but the production HAR
on the new image still showed `GET /api/analytics` at 8 s cold AND the
supposedly-fixed `?slice=summaries` request hit the same 8 s when fired
concurrently. Investigation found the slim slice queues behind the
default slice's per-type live walk: the 15-way `fetchMeasurementSeriesChunked`
fan-out saturates the `p-limit(4)` lanes and packs the 20-slot Prisma
pool for the full ~8 s on Marc's 467 745-row tenant, starving every
other Prisma client (including the concurrent slim slice) until the
walk drains.

The default slice's `summaries` field has been produceable from the
rollup tier for two releases — the slim slice already uses
`computeFromRollups` + a 90-day narrow `$queryRaw` and returns the
identical `DataSummary` shape sub-second. The walk lived on because
two thick-only fields (`anomalyCount`, `avg30LastMonth`) only existed
on the live path. A grep of every consumer in the repo confirmed:

- `anomalyCount`: no consumer reads it from `/api/analytics`. The
  insights pipeline pulls it from its own `comprehensive-aggregator`
  narrow query. Slim's `0` constant is what the default route's
  consumers already received.
- `avg30LastMonth`: read by `src/app/page.tsx:321` (dashboard
  comparison tile) and `src/components/insights/vo2-max-chart-row.tsx`.
  Easy to lift: extend the slim narrow `$queryRaw` with one extra
  FILTER clause for `[30d, 60d)` — the rows are already inside the
  90-day outer cap so the planner reads zero additional blocks.

With both fields covered, `buildAnalyticsResponse` calls
`computeSummariesSlice(user.id)` once and uses its `summaries` +
`lastSeenByType` directly. The 15-way fan-out, the chunked walker,
the `ANALYTICS_TYPE_FETCH_CONCURRENCY` p-limit cap, the 425-day
`since` window, and the `meta.analytics.bp_aggregate` annotate all
delete cleanly — none had callers outside the removed code path.
Net diff: -418 LOC across the route + its tests.

Test updates:
- `route.test.ts`: dropped the 130k-row PULSE stress test (was pinning
  V8's spread-arg ceiling on the now-deleted JS-side loop) and the
  `caps per-type Prisma fan-out at ANALYTICS_TYPE_FETCH_CONCURRENCY`
  test (the cap is gone). Added a negative assertion that
  `prisma.measurement.findMany` is never called with the chunked-walk
  shape `(select.id + source + deviceType, take: 5000)` and a positive
  assertion that `avg30LastMonth` reaches the response envelope.
- `since-cap.test.ts`: dropped the `where.measuredAt.gte` per-type
  assertion and the `bp_aggregate.live_since` annotation assertion
  (both pinned the removed walk). The slim-slice no-per-type-loop
  invariant survives.

Final: 5268 unit + integration tests pass, zero failures, lint clean,
typecheck clean.
2026-05-23 13:25:07 +02:00
..