# Database Migration Review

> Use when performing database migration review — database migration PR review template covering migration safety, rollback planning, table locking analysis, data integrity validation, and production deployment strategy. Provides a systematic framework for reviewing schema changes, data migrations, and index modifications to prevent downtime and data loss.

- Skill: `cloudthinker-ai/database-migration-review` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cloudthinker-ai/database-migration-review`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cloudthinker-ai/database-migration-review/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cloudthinker-ai (https://skillmd.com/u/cloudthinker-ai)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/cloudthinker-ai/database-migration-review

---


# Database Migration Review Skill

Review database migration in PR **#{{ pr_number }}** in **{{ repository }}** for **{{ database_engine }}**.

## Workflow

### Phase 1 — Migration Safety

```
SAFETY CHECK
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[ ] Locking analysis:
    [ ] ALTER TABLE operations assessed for lock duration
    [ ] Large table migrations use online DDL or batching
    [ ] No exclusive locks on high-traffic tables during peak
    [ ] Lock timeout configured
[ ] Backward compatibility:
    [ ] Migration is backward-compatible with current code
    [ ] Column renames use add-copy-drop pattern
    [ ] Column type changes are safe (no data truncation)
    [ ] NOT NULL additions have default values
    [ ] New columns are nullable or have defaults
[ ] Data integrity:
    [ ] Foreign key constraints validated
    [ ] CHECK constraints tested with existing data
    [ ] UNIQUE constraints verified against current data
    [ ] No orphaned records after migration
```

### Phase 2 — Rollback Plan

```
ROLLBACK ASSESSMENT
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[ ] Down migration provided: YES / NO
[ ] Down migration tested: YES / NO
[ ] Rollback is data-safe (no data loss on rollback): YES / NO
[ ] Rollback time estimate: ___
[ ] Point-of-no-return identified: YES / NO
[ ] If irreversible, backup strategy documented: YES / NO
[ ] Rollback steps documented for on-call: YES / NO
```

### Phase 3 — Performance Impact

```
PERFORMANCE IMPACT
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[ ] Index changes:
    [ ] New indexes justified by query patterns
    [ ] Index creation uses CONCURRENTLY (PostgreSQL)
    [ ] Unused indexes identified for removal
    [ ] Composite index column order is optimal
[ ] Table size impact:
    [ ] Estimated table size after migration: ___
    [ ] Migration duration estimate: ___
    [ ] Disk space requirements: ___
[ ] Query impact:
    [ ] Existing queries tested with new schema
    [ ] Query plans reviewed post-migration
    [ ] ORM model changes aligned with schema
```

### Phase 4 — Deployment Strategy

```
DEPLOYMENT PLAN
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[ ] Migration sequence:
    1. Deploy migration (schema change)
    2. Deploy application code
    3. Verify application health
    4. Clean up (drop old columns if needed)
[ ] Maintenance window required: YES / NO
[ ] Expected downtime: ___
[ ] Pre-migration checklist:
    [ ] Database backup taken
    [ ] Migration tested on staging with production-size data
    [ ] Monitoring alerts configured
    [ ] Communication sent to stakeholders
```

## Counter-Rationalizations

| Shortcut | Counter | Why |
|----------|---------|-----|
| "We can skip some steps for this case" | Adapt the workflow steps, don't skip them | Skipped steps are where incidents and oversights originate |
| "The user seems to already know what to do" | Complete all workflow phases with the user | The workflow catches blind spots that experience alone misses |
| "This is a minor case, full process is overkill" | Scale the process down, don't turn it off | Minor cases become major when unstructured; the process scales, not disappears |
| "I'll fill in the details later" | Complete each section before moving on | Deferred details are forgotten; real-time capture is more accurate |
| "The template output isn't necessary" | Always produce the structured output format | Structured output enables comparison, audit trails, and handoff to other teams |

## Output Format

Produce a migration review report with:
1. **Risk assessment** (safe / caution / dangerous)
2. **Locking impact analysis** per operation
3. **Rollback plan evaluation** (reversible / partially / irreversible)
4. **Deployment recommendations** (online / maintenance window / phased)
5. **Specific concerns** with remediation steps