| 2026-06-05 | `6041bac` | Split daily aggregate finalization timings. | The first finalization phase report identified daily aggregate work as the remaining changed-type bottleneck, but `finalizeDailyAggregateElapsed` still mixed affected-bucket lookup, previous aggregate copy, destination delete, affected-bucket rebuild, replacement insert, and residual SQL/transaction overhead. Diagnostics now emit aggregate and per-type daily subphase fields: bucket lookup, copy, delete, rebuild, insert, and other. Follow-up report with `buildFingerprint: 1.0(1)-1780618540-92064` completed in `23.5s`, with `127/127` complete, `CaptureModes: unchangedDelta=118, delta=9`, and `DeltaEvents: 97`. Finalization was `10.5s`, daily aggregate work was `7.4s`, and daily rebuild alone was `6.9s`; daily copy was only `0.5s`. Heart Rate had `40` delta events and spent `4.8s` finalizing, of which `3.8s` was daily aggregate rebuild. Conclusion: copying previous materialized daily rows is not the bottleneck; affected-bucket rebuild scans are. |

 | 2026-06-05 | `bf5a861` | Rebuild changed daily aggregate buckets from time-ranged versions. | Confirmed on two full-profile repeated captures with `buildFingerprint: 1.0(1)-1780640325-92064`. The overnight-data run completed in `21.8s` with `127/127` complete, `CaptureModes: unchangedDelta=111, delta=16`, and `DeltaEvents: 322`; daily aggregate rebuild dropped from `6.9s` to `0.0s`, with daily aggregate work now only `0.6s` copy. The low-delta run completed in `6.6s` with `CaptureModes: unchangedDelta=125, delta=2`; daily aggregate rebuild again stayed `0.0s`. Conclusion: the time-ranged `sample_versions(start_date, sample_id)` query solved the affected-bucket rebuild bottleneck. Continue monitoring first-import insert timing because the new index is a write-path tradeoff. |

 | 2026-06-05 | `e7d45a2` | Count observation events from the event table first. | Confirmed on a full-profile repeated capture with `buildFingerprint: 1.0(1)-1780646299-92064`: wall clock `15.6s`, `127/127` complete, `CaptureModes: unchangedDelta=114, delta=13`, and `DeltaEvents: 99`. `SummedFinalizeEventCountElapsed` dropped from the post-`bf5a861` overnight baseline `2.5s` to `0.0s`; total finalize dropped to `1.7s`, while daily aggregate rebuild stayed `0.0s`. Remaining cost is processing: `9.1s` total, led by Heart Rate `4.6s` for `18` events, Active Energy `1.8s` for `11` events, and Basal Energy `1.5s` for `5` events. |

 ## Current Diagnosis

 - The `e7d45a2` follow-up report validated the event-count query shape:

   `SummedFinalizeEventCountElapsed` dropped to `0.0s` and finalization is no

   longer the active repeated-capture bottleneck.

 - A large older-build first import on an `8.4M`-record database completed but

   took `166m10s`, with `137m31s` summed insert time. This confirms that full

   authorized backup volume can be much larger than the original 15-type test

    identity unless the build provenance is otherwise certain. `sourceCommit`

    and `sourceDirty` are useful when present, but may be `unknown` for normal

    Xcode test installs.

 9. Keep watching first-import insert timing on the next clean large-database

    import because the new `sample_versions(start_date, sample_id)` index from

    `bf5a861` is a write-path tradeoff.

 11. Investigate full-profile empty anchored-query cost for zero-count types.

    Compare slow empty types across reports before changing behavior; any skip or

    lower-frequency strategy must preserve the promise that full authorized

         }

         let archiveRebuildStartedAt = Date()

             typeIdentifier: typeIdentifier,

             previousDistribution: previousDistribution,

             sampleType: sampleType,

             deltaPages: deltaPages

         )

         let archiveRebuildElapsed = Date().timeIntervalSince(archiveRebuildStartedAt)

             records: [],

             contentHash: rebuiltArchive.contentHash,

             yearlyCounts: nil,

             captureMode: .delta,

             deltaEventCount: processedEventCount,

             timingBreakdown: captureTimings.importBreakdown

         )

     }

         typeIdentifier: String,

         previousDistribution: PreviousDistributionState,

         sampleType: HKSampleType,

         deltaPages: [SampleDistributionPage]

         let deltaSampleCount = deltaPages.reduce(0) { $0 + $1.samples.count }

         let deltaDeletedCount = deltaPages.reduce(0) { $0 + $1.deletedObjects.count }

         for page in deltaPages {

             for deletedObject in page.deletedObjects {

             }

             for sample in page.samples {

                 let value = recordValue(for: sample, sampleType: sampleType, typeIdentifier: typeIdentifier)

             }

         }

         )

         return RebuiltRecordArchive(

             count: recordCount,

         )

     }

     let contentHash: String

     let earliestDate: Date?

     let latestDate: Date?

 }

 private final class HealthKitQueryContinuationBox<Value: Sendable>: @unchecked Sendable {

     }

     var canApplyDeltaChanges: Bool {

     }

     init(typeCount: TypeCount?, archiveState: HealthArchiveTypeCaptureState?) {

         if let recordArchiveData {

             typeCount.recordArchiveData = recordArchiveData

             typeCount.setRecordValues(records.map { recordData in

                 HealthRecordValue(

                     typeIdentifier: recordData.typeIdentifier,