# v1.45.0: write path

Same runs as `v1.45.0-read-path.md`.

| request | before p50 ms | after p50 ms | statements before / after |
| --- | ---: | ---: | ---: |
| batch ingest, 500 fresh rows per request | 166 | 186 | 53 / 50 |

Fresh rows were already set-based (v1.44); the benchmark's ingest is all
fresh rows, so it shows no gain, as expected. The changes are for re-posts:

- **Unchanged `stats:` re-posts** write nothing and start nothing. One read
  over the batch's `stats:` ids replaces a reconciler transaction (about ten
  round trips) per row, and an all-unchanged batch no longer refolds, enqueues
  rollups or PR detection, or marks caches stale. The per-entry status stays
  `updated` and the summary's `updated` count is unchanged.
  `tests/integration/routes/measurements-batch-unchanged-stats.test.ts`: four
  unchanged re-posts take at most 12 statements in total (before: about 40)
  with zero rollup, invalidation and PR calls; a changed value, a changed
  device or a tombstoned row still goes through the reconciler.
- **Apple Health re-import** skips the UPDATE of a row stored with exactly the
  values it would write; one read per chunk instead of one UPDATE per row.
  `tests/integration/apple-health-reimport-unchanged.test.ts`: a re-import of
  20 stored rows reports the same per-type counts and sends no UPDATE.
- **Narrower invalidation.** The batch route tells the cache how far back it
  wrote (`touchedFrom`), so closed blocks of older readings stay.