---
phase: 29
plan: 04
subsystem: backend
tags: [migration, backfill, sharp]
key-files:
  created:
    - scripts/backfill-dominant-colors.ts
  modified:
    - package.json
metrics:
  tasks: 2
  commits: 1
  files-changed: 2
---

# Plan 29-04 Summary: Backfill Migration Script

## What was built
- Created `scripts/backfill-dominant-colors.ts` backfill script
- Processes items, globalItems (source URLs + image URLs), and threadCandidates
- Extracts dominant color via Sharp 1x1 resize
- Idempotent: skips records with existing dominantColor
- Batch processing with 10 concurrent requests
- Progress logging per table
- Added `backfill:colors` npm script

## Commits

| Task | Commit | Description |
|------|--------|-------------|
| 1-2 | 6509b33 | Create backfill script and npm shortcut |

## Deviations
None.

## Self-Check: PASSED
- Script exists: YES
- Processes all 3 tables: YES
- Idempotent (isNull check): YES
- Batch size 10: YES
- Progress logging: YES
- npm script exists: YES
- Lint passes: YES