---
phase: 05-deploy-gap-repair
plan: 01
subsystem: backfill
tags: [microseconds, timestamps, trailing-edge, backfill, clickhouse]

# Dependency graph
requires:
  - phase: 04-python-sql-rename
    provides: "CH columns renamed from _ms to _us (close_time_us, open_time_us)"
provides:
  - "backfill_gap() with correct microsecond arithmetic for trailing edge"
  - "Tests using microsecond mock values matching CH return types"
affects: [deploy-pipeline, sidecar-gap-fill]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "us→ms conversion via // 1000 at REST API boundary"

key-files:
  created: []
  modified:
    - python/opendeviationbar/backfill.py
    - tests/test_committed_fixes.py

key-decisions:
  - "REST API calls receive ms via explicit // 1000 conversion from us values"

patterns-established:
  - "Timestamp boundary pattern: internal computation in us, REST API calls in ms via // 1000"

requirements-completed: [BFILL-01, BFILL-02]

# Metrics
duration: 2min
completed: 2026-03-25
---

# Phase 05 Plan 01: Deploy Gap Repair Summary

**Fixed backfill_gap() ms-to-us unit mismatch that caused negative gap_seconds and broke all trailing-edge repairs**

## Performance

- **Duration:** 2 min
- **Started:** 2026-03-25T02:46:08Z
- **Completed:** 2026-03-25T02:48:07Z
- **Tasks:** 1 (TDD: RED + GREEN)
- **Files modified:** 2

## Accomplishments

- Fixed `now_ms` to `now_us` (microsecond computation matching CH return values)
- Fixed `gap_ms` to `gap_us` with correct `/1_000_000.0` conversion to seconds
- Added `// 1000` conversion at REST API boundary (REST expects ms)
- Updated test mocks from millisecond to microsecond timestamps

## Task Commits

Each task was committed atomically (TDD flow):

1. **Task 1 RED: Failing tests for us/ms mismatch** - `9e1ba44` (test)
2. **Task 1 GREEN: Fix backfill_gap() to use microseconds** - `1068b53` (fix)

## Files Created/Modified

- `python/opendeviationbar/backfill.py` - Fixed trailing edge: now_us, gap_us, us→ms conversion for REST
- `tests/test_committed_fixes.py` - Updated mock timestamps from ms to us (matching CH return values)

## Decisions Made

- REST API boundary conversion uses integer division `// 1000` (truncation is correct for trade ID pagination start_ms)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

- backfill_gap() now correctly computes trailing edge gaps in microseconds
- All 9 tests in test_committed_fixes.py pass
- Ready for Phase 06 (deploy pipeline integration) if applicable

---

_Phase: 05-deploy-gap-repair_
_Completed: 2026-03-25_

## Self-Check: PASSED
