145 lines
4.2 KiB
Markdown
145 lines
4.2 KiB
Markdown
# 🏗️ Enterprise Database Migration Strategy
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## 🚨 Current Issues Identified
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### Critical Problems
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1. **No Migration State Tracking** - Migrations run repeatedly causing conflicts
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2. **Schema Duplication** - Migration 017 recreates entire schema (20KB)
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3. **Inconsistent Patterns** - Mix of idempotent and non-idempotent operations
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4. **Missing Versioning** - No proper version control or rollback capability
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5. **Conflicting Constraints** - Same columns added with different FK behaviors
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### Impact Assessment
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- **High Risk**: Production deployments may fail
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- **Data Integrity**: Potential for inconsistent schema states
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- **Maintenance**: Extremely difficult to debug and maintain
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- **Scalability**: Cannot handle complex schema evolution
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## 🎯 Recommended Solution Architecture
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### 1. Migration Tracking System
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```sql
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-- Core tracking table
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schema_migrations (
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version, filename, checksum, applied_at,
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execution_time_ms, success, error_message
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)
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-- Concurrency control
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migration_locks (
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locked_at, locked_by, process_id
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)
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```
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### 2. Enterprise Migration Runner
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- **State Tracking**: Records all migration attempts
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- **Checksum Validation**: Prevents modified migrations from re-running
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- **Concurrency Control**: Prevents parallel migration execution
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- **Error Handling**: Distinguishes between fatal and idempotent errors
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- **Rollback Support**: Tracks rollback instructions
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### 3. Migration Naming Convention
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```
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XXX_descriptive_name.sql
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├── 000_migration_tracking_system.sql # Infrastructure
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├── 001_core_tables.sql # Core schema
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├── 002_indexes_and_constraints.sql # Performance
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├── 003_user_management.sql # Features
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└── 999_data_cleanup.sql # Maintenance
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```
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## 🔧 Implementation Plan
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### Phase 1: Infrastructure Setup ✅
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- [x] Create migration tracking system (`000_migration_tracking_system.sql`)
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- [x] Build enterprise migration runner (`migrate_v2.js`)
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- [x] Add conflict resolution (`021_cleanup_migration_conflicts.sql`)
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### Phase 2: Migration Cleanup (Recommended)
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1. **Backup Current Database**
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2. **Run New Migration System**
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3. **Validate Schema Consistency**
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4. **Remove Duplicate Migrations**
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### Phase 3: Process Improvement
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1. **Code Review Process** for all new migrations
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2. **Testing Strategy** with migration rollback tests
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3. **Documentation Standards** for complex schema changes
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## 📋 Migration Best Practices
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### DO ✅
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- Always use `IF NOT EXISTS` for idempotent operations
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- Include rollback instructions in comments
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- Test migrations on copy of production data
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- Use transactions for multi-step operations
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- Document breaking changes clearly
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### DON'T ❌
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- Never modify existing migration files
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- Don't create massive "complete schema" migrations
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- Avoid mixing DDL and DML in same migration
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- Don't skip version numbers
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- Never run migrations manually in production
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## 🚀 Quick Start Guide
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### 1. Initialize New System
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```bash
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# Run the new migration system
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node src/migrations/migrate_v2.js
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```
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### 2. Verify Status
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```sql
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-- Check migration history
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SELECT * FROM get_migration_history();
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-- Get current version
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SELECT get_current_schema_version();
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```
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### 3. Create New Migration
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```bash
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# Follow naming convention
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touch 022_add_new_feature.sql
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```
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## 📊 Schema Health Metrics
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### Current State
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- **Tables**: 41 total
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- **Migrations**: 21 files (20 + tracking)
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- **Conflicts**: Multiple (resolved in 021)
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- **Duplications**: High (migration 017)
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### Target State
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- **Tracking**: Full migration history
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- **Consistency**: Zero schema conflicts
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- **Performance**: Optimized indexes
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- **Maintainability**: Clear migration path
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## 🔍 Monitoring & Maintenance
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### Regular Checks
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1. **Weekly**: Review failed migrations
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2. **Monthly**: Analyze schema drift
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3. **Quarterly**: Performance optimization review
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### Alerts
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- Migration failures
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- Long-running migrations (>5 minutes)
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- Schema inconsistencies between environments
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## 🎯 Success Criteria
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- ✅ Zero migration conflicts
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- ✅ Full state tracking
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- ✅ Rollback capability
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- ✅ Performance optimization
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- ✅ Documentation compliance
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---
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**Next Steps**: Run the new migration system and validate all schema objects are correctly created with proper relationships and constraints.
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