# v1.45.0: read path

Request benchmark on the seeded account (1,265,561 rows), production build,
web process, heap ceiling 792 MB, 20 requests per row, one at a time.
`v1.45.0-before` is the v1.44 runtime (1915f9152), `v1.45.0-final` this
branch; both on the same machine within the hour, load average 7 to 30
(other work on the host), so latency compares within a factor of noise and
statements exactly. Cold means every request follows a one-row manual sync.

| request | before p50 / p95 ms | after p50 / p95 ms | statements before / after |
| --- | ---: | ---: | ---: |
| dashboard snapshot, cold | 1482 / 1526 | 545 / 593 | 158 / 153 |
| dashboard summary, cold | 170 / 221 | 87 / 101 | 31 / 30 |
| series pulse 3650 d, cold | 1627 / 1665 | 335 / 349 | 8 / 7 |
| series pulse 3650 d, warm | 2091 / 2435 | 328 / 346 | 8 / 7 |
| series pulse 365 d, cold | 184 / 193 | 41 / 56 | 8 / 7 |
| series pulse 30 d, cold | 24 / 31 | 19 / 27 | 8 / 8 |
| insights health status, cold | 245 / 401 | 156 / 190 | 68 / 67 |

What moved them:

- **JIT off for app sessions.** Postgres compiled every fold whose estimated
  cost passed `jit_above_cost`; on the ten-year pulse pick that was 100 to
  140 ms of a 220 ms statement (`EXPLAIN ANALYZE`: 395 ms with JIT, 220 ms
  without).
- **The canonical-source pick groups first.** `DISTINCT ON` now sorts the
  distinct `(type, day, source)` triples instead of every raw reading (the
  ten-year pulse pick sorted 260,000 rows and spilled to disk); 220 ms to
  175 ms on its own. Parity: `tests/integration/canonical-source-pick-parity.test.ts`
  runs the old statement beside the new one over five reader shapes and two
  ladders on a fixture with overlapping and off-ladder sources, tombstones,
  empty days and readings around midnight; identical rows.
- **The dense series reads its rows once.** Buckets and strip figures come
  from one statement over a materialised window instead of two statements
  that each picked the canonical source and scanned the readings. Parity:
  `tests/integration/dense-series-read-parity.test.ts`, the two old
  statements as reference, pulse (two ranked sources), glucose and oxygen
  saturation, day and hour grains, UTC, Europe/Berlin, Asia/Kolkata and
  America/New_York; identical buckets and figures (relative 1e-9).
- **Closed blocks survive a sync.** The slice's pre-fold remainder (every
  reading older than five years, the snapshot's largest statement at 357 ms)
  and the day view's past history blocks are cached under a key that names
  the instant their readings end before; a sync of newer readings no longer
  drops them (`src/lib/cache/closed-block.ts`). The values are the same
  statement's; only how long they are kept changed.