# Production Migration Checklist

## 🎯 Pre-Migration Requirements
**ALL items must be completed before production migration**

### ✅ Testing Validation
- [ ] **100% sandbox migration success** - All tables migrated without errors
- [ ] **Data integrity verified** - Record counts match exactly between SQLite/PostgreSQL
- [ ] **Performance acceptable** - Migration completes within maintenance window
- [ ] **Rollback tested** - Confirmed ability to revert to SQLite if needed
- [ ] **Team sign-off** - Technical and business stakeholders approve migration

### ✅ Infrastructure Readiness
- [ ] **PostgreSQL server provisioned** - Production hardware/cloud resources ready
- [ ] **Backup systems configured** - Automated backups for PostgreSQL
- [ ] **Monitoring enabled** - Database performance and health monitoring
- [ ] **Security hardened** - Access controls, encryption, firewall rules
- [ ] **Network connectivity** - Application servers can reach PostgreSQL

### ✅ Application Readiness
- [ ] **Environment variables updated** - `DATABASE_TYPE=postgresql` in production
- [ ] **Connection pooling configured** - Appropriate pool sizes for PostgreSQL
- [ ] **Dependencies updated** - `psycopg2-binary` installed in production
- [ ] **Query compatibility verified** - All LIKE queries use ILIKE where needed
- [ ] **Error handling updated** - PostgreSQL-specific error codes handled

---

## 🚀 Migration Day Execution Plan

### Phase 1: Pre-Migration (T-2 hours)
- [ ] **Notify stakeholders** - Send migration start notification
- [ ] **Application maintenance mode** - Put application in read-only mode
- [ ] **Final SQLite backup** - Create point-in-time backup
- [ ] **PostgreSQL preparation** - Ensure target database is ready
- [ ] **Team assembly** - All migration team members available

### Phase 2: Data Migration (T-0 to T+X)
- [ ] **Start migration script** - Begin `migrate_to_postgres.py`
- [ ] **Monitor progress** - Track migration status and performance
- [ ] **Handle issues** - Apply pre-tested fixes for any problems
- [ ] **Validate data integrity** - Run `validate_migration.py`
- [ ] **Performance verification** - Test key application queries

### Phase 3: Application Cutover (T+X to T+Y)
- [ ] **Update environment variables** - Switch to PostgreSQL
- [ ] **Restart application services** - Deploy with PostgreSQL configuration
- [ ] **Connection testing** - Verify application connects successfully
- [ ] **Functional testing** - Test critical user workflows
- [ ] **Performance monitoring** - Watch for performance issues

### Phase 4: Go-Live Verification (T+Y to T+Z)
- [ ] **Remove maintenance mode** - Enable full application access
- [ ] **User acceptance testing** - Key users verify functionality
- [ ] **Performance monitoring** - Monitor system under user load
- [ ] **Data consistency checks** - Ongoing validation of data integrity
- [ ] **Issue escalation** - Address any problems immediately

---

## 🔄 Rollback Procedures

### Immediate Rollback Triggers
- **Data corruption detected** - Any indication of data loss or corruption
- **Performance degradation > 5x** - Unacceptable application performance
- **Critical functionality broken** - Core features not working
- **Security concerns** - Any security-related issues discovered
- **Team consensus** - Migration team agrees rollback is necessary

### Rollback Execution (Emergency)
```bash
# 1. Immediate application switch
export DATABASE_TYPE=sqlite
systemctl restart application

# 2. Verify SQLite connectivity
python test_sqlite_connection.py

# 3. Notify stakeholders
send_rollback_notification.sh

# 4. Document issues
echo "Rollback executed at $(date): $(reason)" >> rollback_log.md
```

### Post-Rollback Actions
- [ ] **Root cause analysis** - Identify what went wrong
- [ ] **Issue documentation** - Update migration issues tracker
- [ ] **Fix development** - Address problems in sandbox
- [ ] **Retest thoroughly** - Validate fixes before retry
- [ ] **Stakeholder communication** - Explain rollback and next steps

---

## 📊 Success Criteria

### Quantitative Metrics
- **Migration time**: < 4 hours total
- **Data accuracy**: 100% record count match
- **Query performance**: < 2x SQLite response times
- **Downtime**: < 1 hour application unavailability
- **Error rate**: 0 critical errors during migration

### Qualitative Indicators
- **User experience**: No degradation in functionality
- **System stability**: No crashes or instability
- **Team confidence**: High confidence in system reliability
- **Monitoring clean**: No critical alerts or warnings
- **Documentation current**: All procedures documented

---

## 🔧 Emergency Contacts

### Technical Team
- **Database Admin**: [contact] - PostgreSQL expertise
- **Application Lead**: [contact] - Application configuration
- **DevOps Engineer**: [contact] - Infrastructure support
- **QA Lead**: [contact] - Testing and validation

### Business Team
- **Product Owner**: [contact] - Business impact decisions
- **Operations Manager**: [contact] - User communication
- **Security Officer**: [contact] - Security concerns
- **Compliance Lead**: [contact] - Regulatory requirements

---

## 📋 Pre-Flight Checklist (Final 24 Hours)

### Technical Verification
- [ ] **Sandbox migration** - Final successful test run completed
- [ ] **Production database** - PostgreSQL server health verified
- [ ] **Backup systems** - All backup procedures tested
- [ ] **Monitoring dashboards** - All alerts and monitors active
- [ ] **Rollback plan** - Tested and verified within 2 hours

### Operational Readiness
- [ ] **Team availability** - All key personnel confirmed available
- [ ] **Communication plan** - Stakeholder notifications prepared
- [ ] **Change control** - All approvals and documentation complete
- [ ] **Risk assessment** - Mitigation strategies for known risks
- [ ] **Go/No-Go decision** - Final stakeholder approval received

### Documentation Current
- [ ] **Migration procedures** - Step-by-step instructions updated
- [ ] **Troubleshooting guides** - Known issues and solutions documented
- [ ] **Contact information** - All emergency contacts verified
- [ ] **Rollback procedures** - Clear instructions for reverting changes
- [ ] **Post-migration tasks** - Cleanup and optimization steps defined

---

## 📈 Post-Migration Activities

### Immediate (24 hours)
- [ ] **Performance monitoring** - Watch system metrics closely
- [ ] **User feedback collection** - Gather user experience reports
- [ ] **Data validation** - Ongoing verification of data integrity
- [ ] **Issue tracking** - Document any problems discovered
- [ ] **Team debrief** - Capture lessons learned

### Short-term (1 week)
- [ ] **Performance optimization** - Tune PostgreSQL configuration
- [ ] **Index optimization** - Create additional indexes if needed
- [ ] **Monitoring refinement** - Adjust alert thresholds
- [ ] **Documentation updates** - Update operational procedures
- [ ] **Training completion** - Ensure team is trained on PostgreSQL

### Long-term (1 month)
- [ ] **SQLite decommission** - Remove old SQLite infrastructure
- [ ] **Backup verification** - Validate PostgreSQL backup/restore
- [ ] **Performance baseline** - Establish new performance standards
- [ ] **Security audit** - Complete security review of new system
- [ ] **Success metrics** - Measure and report migration success

---

## 🎯 Final Authorization

### Sign-off Required
- [ ] **Database Administrator**: _________________ Date: _________
- [ ] **Application Lead**: _________________ Date: _________  
- [ ] **DevOps Engineer**: _________________ Date: _________
- [ ] **QA Lead**: _________________ Date: _________
- [ ] **Product Owner**: _________________ Date: _________
- [ ] **Security Officer**: _________________ Date: _________

### Migration Approval
**Authorized to proceed with production migration**: YES / NO

**Authorized by**: _________________ **Date**: _________ **Time**: _________

**Migration window**: Start: _________ End: _________

**Rollback deadline**: _________

---

*This checklist ensures systematic, safe migration to production with clear success criteria and rollback procedures.*