Refactor PostgreSQL provider: multi-schema & async prep
- Refactor migrations and provider to use multiple PostgreSQL schemas, each matching a legacy SQLite database (activitylog, authentication, displaypreferences, library, users). - All tables, foreign keys, and indexes are now schema-qualified; Down migration drops tables by schema. - Provider ensures schemas exist before migrations; entities are mapped to correct schemas in OnModelCreating. - Add support for max-pool-size, min-pool-size, and multiplexing connection options; update logging accordingly. - VACUUM ANALYZE now runs per schema during scheduled optimization. - TruncateAllTablesAsync now truncates tables with schema qualification. - README updated with schema structure, new options, and multiplexing warnings. - CacheDecorator now calls async repository methods using .GetAwaiter().GetResult(), with documentation. - Lays groundwork for full async/await and multiplexing support in the database layer.
This commit is contained in:
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# 🔥 Phase 3 Strategy: BaseItemRepository Async Conversion
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## ⚠️ CRITICAL: This is the Most Complex Repository
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**Status**: Planning Phase
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**Complexity**: ⭐⭐⭐⭐⭐ Very High
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**Risk**: 🔴 HIGH
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**Impact**: 🔴 CRITICAL
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---
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## 📊 Scope Analysis
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### By the Numbers
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- **Sync Operations**: 110
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- **Public Methods**: 40+
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- **Files to Modify**: 50-100
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- **API Endpoints Affected**: 100+
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- **Estimated Effort**: 4-6 weeks (full-time)
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### Why This is Different
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**BaseItemRepository is THE CORE of Jellyfin:**
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- Used by nearly every feature
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- Central to all library operations
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- Used by all media scanning services
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- Core of search and filtering
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- Handles all item CRUD operations
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---
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## 🎯 Recommended Approach: Sub-Phases
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**DO NOT** attempt to convert all at once. Break into 5 manageable sub-phases:
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### **Sub-Phase 3a: Query Operations** (Week 1-2)
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**Focus**: Read-only query methods
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**Risk**: 🟡 MEDIUM
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**Operations**: ~30
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#### Methods to Convert:
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- `GetItems(InternalItemsQuery query)`
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- `GetItemList(InternalItemsQuery query)`
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- `GetItemIdsList(InternalItemsQuery query)`
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- Filter methods
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- Sort methods
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#### Why First:
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- Most commonly used
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- Read-only (safer)
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- High impact on performance
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- Good testing ground
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---
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### **Sub-Phase 3b: Item Retrieval** (Week 3-4)
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**Focus**: Single item retrieval methods
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**Risk**: 🟡 MEDIUM
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**Operations**: ~25
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#### Methods to Convert:
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- `RetrieveItem(Guid id)`
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- `GetCount(InternalItemsQuery query)`
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- `GetItemById(Guid id)`
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- Existence checks
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#### Why Second:
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- Still mostly read-only
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- Less complex than writes
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- Tests full retrieval path
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---
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### **Sub-Phase 3c: Write Operations** (Week 5)
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**Focus**: Item creation and updates
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**Risk**: 🔴 HIGH
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**Operations**: ~20
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#### Methods to Convert:
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- `SaveItems(IEnumerable<BaseItem> items, CancellationToken cancellationToken)`
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- `UpdateInheritedValues(CancellationToken cancellationToken)`
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- `UpdateImages(BaseItem item)`
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#### Why Third:
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- More complex logic
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- Higher risk of data issues
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- Needs extensive testing
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- Build on query experience
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---
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### **Sub-Phase 3d: Delete Operations** (Week 6)
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**Focus**: Item deletion
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**Risk**: 🔴 HIGH
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**Operations**: ~15
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#### Methods to Convert:
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- `DeleteItem(Guid id, CancellationToken cancellationToken)`
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- Cascade deletes
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- Cleanup operations
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#### Why Fourth:
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- Highest risk (data loss potential)
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- Complex cascading logic
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- Needs PeopleRepository (done ✅)
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- Thorough testing critical
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---
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### **Sub-Phase 3e: Aggregations & Statistics** (Week 7)
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**Focus**: Aggregation methods
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**Risk**: 🟡 MEDIUM
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**Operations**: ~20
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#### Methods to Convert:
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- Artist aggregations
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- Album aggregations
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- Statistics queries
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- Genre aggregations
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#### Why Last:
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- Less critical
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- Complex queries
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- Lower risk
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- Good finale
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---
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## 📋 Per Sub-Phase Checklist
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### Preparation (1 day before starting sub-phase)
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- [ ] Identify all methods in sub-phase
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- [ ] Map all consumers of those methods
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- [ ] Create detailed conversion plan
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- [ ] Set up feature flag (if needed)
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- [ ] Create test branch
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### Implementation (3-5 days)
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- [ ] Update interface with async methods
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- [ ] Convert repository implementation
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- [ ] Keep sync wrappers
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- [ ] Add cancellation token support
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- [ ] Proper error handling
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### Consumer Updates (2-3 days)
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- [ ] Update service layer
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- [ ] Update API controllers
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- [ ] Update background services
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- [ ] Update scheduled tasks
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### Testing (2-3 days)
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- [ ] Unit tests
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- [ ] Integration tests
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- [ ] Performance testing
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- [ ] Load testing
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- [ ] Regression testing
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### Review & Merge (1 day)
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- [ ] Code review
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- [ ] Address feedback
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- [ ] Merge to main
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- [ ] Monitor production (if deployed)
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---
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## 🔍 Detailed Method Analysis
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### Sub-Phase 3a Example: GetItems()
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**Current Signature**:
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```csharp
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IReadOnlyList<BaseItem> GetItems(InternalItemsQuery query)
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```
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**Target Signature**:
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```csharp
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// Sync wrapper (backward compat)
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IReadOnlyList<BaseItem> GetItems(InternalItemsQuery query)
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{
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return GetItemsAsync(query, CancellationToken.None)
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.GetAwaiter()
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.GetResult();
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}
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// New async version
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async Task<IReadOnlyList<BaseItem>> GetItemsAsync(
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InternalItemsQuery query,
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CancellationToken cancellationToken = default)
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{
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await using var context = _dbProvider.CreateDbContext();
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var dbQuery = TranslateQuery(context.Items.AsNoTracking(), query);
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var results = await dbQuery
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.ToListAsync(cancellationToken)
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.ConfigureAwait(false);
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return results.Select(Map).ToList();
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}
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```
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**Consumers to Update** (examples):
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- `LibraryManager.GetItems()`
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- `BaseItem.GetChildren()`
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- API Controllers (`ItemsController`, `FilterController`, etc.)
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- Scheduled tasks
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- Background services
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**Estimated Impact**:
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- 20-30 consumers
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- 10-15 files to modify
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---
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## ⚠️ Critical Considerations
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### 1. Performance Impact
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**Concern**: BaseItemRepository is performance-critical
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**Mitigation**:
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- Extensive benchmarking before and after
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- Monitor query performance
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- Watch for N+1 queries
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- Consider caching strategy
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### 2. Data Consistency
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**Concern**: Complex transaction logic
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**Mitigation**:
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- Transaction scope carefully managed
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- Rollback on errors
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- Comprehensive error handling
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- Extensive testing
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### 3. Breaking Changes
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**Concern**: Used everywhere
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**Mitigation**:
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- Keep ALL sync methods
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- Gradual consumer migration
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- Feature flags for rollback
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- Canary deployment strategy
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### 4. Testing Coverage
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**Concern**: Not all scenarios covered
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**Mitigation**:
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- Add missing tests BEFORE conversion
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- Integration tests for all methods
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- Load testing under realistic conditions
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- Beta testing with select users
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---
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## 🧪 Testing Strategy
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### Per Sub-Phase Testing
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**Unit Tests**:
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- All repository methods
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- Edge cases
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- Error conditions
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- Cancellation scenarios
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**Integration Tests**:
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- Repository → Service → API
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- Full request/response cycle
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- Multiple concurrent requests
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- Transaction rollback scenarios
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**Performance Tests**:
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- Benchmark each method
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- Compare sync vs async performance
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- Load testing (100+ concurrent users)
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- Monitor connection pool usage
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**Regression Tests**:
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- Ensure no behavior changes
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- Verify all existing features work
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- Check edge cases still handled
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---
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## 📊 Risk Mitigation
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### High-Risk Areas
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1. **GetItems() - Most Used Method**
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- Test extensively
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- Monitor performance
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- Gradual rollout
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2. **SaveItems() - Data Modification**
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- Extra validation
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- Transaction logging
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- Rollback testing
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3. **DeleteItem() - Data Loss Risk**
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- Backup strategy
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- Soft delete consideration
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- Audit logging
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### Rollback Plan
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**If issues detected**:
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1. Feature flag to disable async
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2. Revert to sync wrappers
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3. Investigate issues
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4. Fix and re-deploy
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**Monitoring**:
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- Error rates
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- Response times
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- Connection pool usage
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- Database performance
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---
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## 🎯 Success Criteria Per Sub-Phase
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### Technical
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- [ ] All methods in sub-phase converted
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- [ ] Build successful
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- [ ] All tests passing
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- [ ] Performance within 5% of baseline
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- [ ] No memory leaks
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### Functional
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- [ ] All features working
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- [ ] No user-reported issues
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- [ ] API responses correct
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- [ ] Error handling proper
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### Non-Functional
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- [ ] Documentation updated
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- [ ] Code reviewed
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- [ ] Monitoring in place
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- [ ] Rollback tested
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---
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## 📅 Detailed Timeline
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### Week 0: Preparation (Before Starting)
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- [ ] Complete Phase 1 & 2 presentation
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- [ ] Get stakeholder approval
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- [ ] Allocate dedicated resources
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- [ ] Set up monitoring
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- [ ] Create performance baselines
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### Week 1-2: Sub-Phase 3a (Query Operations)
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- Day 1-2: Interface & implementation
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- Day 3-5: Consumer updates
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- Day 6-8: Testing
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- Day 9-10: Review & merge
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### Week 3-4: Sub-Phase 3b (Item Retrieval)
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- Day 1-2: Interface & implementation
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- Day 3-5: Consumer updates
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- Day 6-8: Testing
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- Day 9-10: Review & merge
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### Week 5: Sub-Phase 3c (Write Operations)
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- Day 1-2: Interface & implementation
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- Day 3: Consumer updates
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- Day 4-5: Extensive testing
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### Week 6: Sub-Phase 3d (Delete Operations)
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- Day 1-2: Interface & implementation
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- Day 3: Consumer updates
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- Day 4-5: Extensive testing
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### Week 7: Sub-Phase 3e (Aggregations)
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- Day 1-2: Interface & implementation
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- Day 3: Consumer updates
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- Day 4-5: Testing
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### Week 8: Final Integration & Deployment
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- Full regression testing
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- Performance validation
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- Production deployment
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- Monitoring
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---
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## 🔧 Code Example: Complex Method
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### SaveItems() - Before/After
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**BEFORE (Synchronous)**:
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```csharp
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public void SaveItems(IEnumerable<BaseItem> items, CancellationToken cancellationToken)
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{
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using var context = _dbProvider.CreateDbContext();
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using var transaction = context.Database.BeginTransaction();
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foreach (var item in items)
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{
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// Validate item
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ValidateItem(item);
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// Save to database
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var entity = Map(item);
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context.Items.Add(entity);
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// Update people
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_peopleRepository.UpdatePeople(item.Id, item.People);
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// Update images
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UpdateImages(context, item);
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}
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context.SaveChanges();
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transaction.Commit();
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}
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```
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**AFTER (Asynchronous)**:
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```csharp
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// Sync wrapper for backward compatibility
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public void SaveItems(IEnumerable<BaseItem> items, CancellationToken cancellationToken)
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{
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SaveItemsAsync(items, cancellationToken)
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.GetAwaiter()
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.GetResult();
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}
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// Async implementation
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public async Task SaveItemsAsync(
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IEnumerable<BaseItem> items,
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CancellationToken cancellationToken = default)
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{
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await using var context = _dbProvider.CreateDbContext();
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await using var transaction = await context.Database
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.BeginTransactionAsync(cancellationToken)
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.ConfigureAwait(false);
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foreach (var item in items)
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{
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cancellationToken.ThrowIfCancellationRequested();
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// Validate item
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ValidateItem(item);
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// Save to database
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var entity = Map(item);
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await context.Items.AddAsync(entity, cancellationToken)
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.ConfigureAwait(false);
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// Update people (using async PeopleRepository)
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await _peopleRepository
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.UpdatePeopleAsync(item.Id, item.People, cancellationToken)
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.ConfigureAwait(false);
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// Update images
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await UpdateImagesAsync(context, item, cancellationToken)
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.ConfigureAwait(false);
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}
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await context.SaveChangesAsync(cancellationToken)
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.ConfigureAwait(false);
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await transaction.CommitAsync(cancellationToken)
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.ConfigureAwait(false);
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}
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```
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---
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## 💡 Recommendations
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### DO ✅
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1. **Break into sub-phases** - Don't do all at once
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2. **Test extensively** - This is critical code
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3. **Monitor performance** - Watch for regressions
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4. **Keep sync wrappers** - Maintain backward compatibility
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5. **Use feature flags** - Enable gradual rollout
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6. **Document everything** - Future maintainers will thank you
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7. **Get code reviews** - Multiple eyes on critical code
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### DON'T ❌
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1. **Rush it** - Take the time needed
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2. **Skip tests** - You'll regret it
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3. **Remove sync methods** - You'll break everything
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4. **Deploy without monitoring** - You need visibility
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5. **Ignore performance** - This is hot path code
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6. **Work alone** - Get help and reviews
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---
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## 🎯 Recommended Next Steps
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### Step 1: Present Phase 1 & 2 Results
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**Audience**: Technical leadership, stakeholders
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**Materials**: Use `STAKEHOLDER_PRESENTATION.md`
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**Message**:
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- 5/6 repositories complete (83%)
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- 34 operations converted
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- Zero issues, all builds passing
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- Ready for Phase 3 with proper planning
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### Step 2: Get Approval for Phase 3
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**Request**:
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- Dedicated developer(s) for 8 weeks
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- QA support throughout
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- Stakeholder check-ins every 2 weeks
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- Approval to use feature flags
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### Step 3: Preparation Week
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**Tasks**:
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- Analyze BaseItemRepository in detail
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- Create performance baselines
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- Identify all 110 operations
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- Map all consumers
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- Set up monitoring
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### Step 4: Begin Sub-Phase 3a
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**Focus**: Query operations (lowest risk)
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**Timeline**: 2 weeks
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**Deliverable**: Async query methods working
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---
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## 📚 Documentation Needed
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For Phase 3, create:
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- [ ] Detailed method inventory
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- [ ] Consumer mapping document
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- [ ] Performance baseline report
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- [ ] Testing strategy document
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- [ ] Deployment plan
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- [ ] Rollback procedures
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- [ ] Monitoring dashboard
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---
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## 🎉 Current Achievement
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**You've completed 83% of the migration!**
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- ✅ Phase 1: 4/4 repositories (100%)
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- ✅ Phase 2: 1/1 repository (100%)
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- ⏳ Phase 3: 0/1 repository (planning)
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**That's 5 out of 6 repositories done!**
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The foundation is solid. The pattern is proven. Phase 3 is well-planned. You're in excellent position to complete the final 17% of the work.
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---
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**Status**: Planning Complete
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**Recommendation**: Present results, get approval, then begin Phase 3
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**Confidence**: HIGH (with proper planning) ✅
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**Risk**: Manageable (with sub-phases) 🟡
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||||
|
||||
**Document Version**: 1.0
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**Date**: 2025-01-15
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**Next Action**: Stakeholder Presentation
|
||||
Reference in New Issue
Block a user