Record post-index-removal import result · 4a2ba49

+45 -1

HealthProbe/Doc/04-project/Import-Optimization-Log.md

+                     a large measurable gain. SQLite insert remains dominant, but the main bottleneck
+                     has moved from about 14m38s to 10m11s.
+                    +### 2026-06-02 First Import After Additional Index Removal
+                    +Commit context: after `06ee6be` (`Drop additional import write indexes`). Source:
+                    +user-provided diagnostic report with `previousSnapshotID: none`,
+                    +`isChainStart: true`, and the same total record count as the previous clean run.
+                    +This is a comparable first-import benchmark for removing
+                    +`idx_sample_versions_time` and `idx_visibility_sample_open`.
+                    +| Metric | Value |
+                    +|--------|-------|
+                    +| Wall clock | 12m 39s |
+                    +| Summed metric total | 12m 39s |
+                    +| Summed fetch | 43.8s |
+                    +| Summed processing | 1m 35s |
+                    +| Summed insert | 10m 07s |
+                    +| Summed finalize | 10.1s |
+                    +| Total records | 1,579,168 |
+                    +| Heart Rate count | 922,450 |
+                    +| Heart Rate total | 8m 08s |
+                    +| Heart Rate fetch | 19.2s |
+                    +| Heart Rate processing | 55.0s |
+                    +| Heart Rate insert | 6m 44s |
+                    +| Active Energy count | 348,701 |
+                    +| Active Energy insert | 2m 07s |
+                    +| Steps insert | 20.7s |
+                    +| Walking + Running Distance insert | 18.2s |
+                    +Comparison against the previous comparable first-import run (`3dd5f48` context):
+                    +| Metric | Previous | Current | Change |
+                    +|--------|----------|---------|--------|
+                    +| Wall clock | 12m 43s | 12m 39s | -4s / -1% |
+                    +| Summed insert | 10m 11s | 10m 07s | -4s / -1% |
+                    +| Heart Rate insert | 6m 41s | 6m 44s | +3s / +1% |
+                    +| Active Energy insert | 2m 09s | 2m 07s | -2s / -2% |
+                    +| Steps insert | 21.6s | 20.7s | -0.9s / -4% |
+                    +| Walking + Running Distance insert | 19.2s | 18.2s | -1.0s / -5% |
+                    +Conclusion: removing these two extra indexes did not materially change first
+                    +import performance. The small differences are within expected run-to-run noise.
+                    +The larger first-import gain remains attributable to the earlier hot `samples`
+                    +index removal plus clean reset conditions.
+                     ## Optimization Iterations
+                     | Date | Commit | Change | Result / Status |
+                     | 2026-06-02 | pending | Captured non-chain-start full-scan report after index removal. | Not comparable for first-import performance; reveals a separate full-scan/unchanged-sample write bottleneck. |
+                     | 2026-06-02 | `a281c51` | Stopped writing `verified` observation events for unchanged existing samples. | Awaiting comparable non-chain-start/full-scan report. Expected signal is lower `SummedInsertElapsed` and especially lower Heart Rate insert time when most rows are unchanged. |
+                     | 2026-06-02 | `3dd5f48` | Fortified scheduled test database reset with a disk marker and extra SQLite sidecar cleanup. | Real-device report confirmed reset produced `previousSnapshotID: none`, `isChainStart: true`, and a clean first-snapshot timeline. |
+                    -| 2026-06-02 | pending | Removed unused `sample_versions(start_date, end_date)` and redundant `sample_visibility_ranges(sample_id, last_observation_id)` indexes. | Awaiting comparable first-import report. Expected signal is lower insert time because first import writes one sample version and one visibility range per record. |
+                    +| 2026-06-02 | `06ee6be` | Removed unused `sample_versions(start_date, end_date)` and redundant `sample_visibility_ranges(sample_id, last_observation_id)` indexes. | Comparable first-import report was flat: wall clock 12m43s -> 12m39s and summed insert 10m11s -> 10m07s. Treat as no material performance change. |
+                     ## Current Diagnosis