# Database Issues Fix Summary

**Date**: 2025-09-30
**Fixed By**: Claude Code (Sonnet 4.5)

## Critical Issue Resolved

### 1. Multi-Word Search Failure (HIGH PRIORITY) - FIXED ✓

**Problem**: Queries with multiple words like "memory system test" returned 0 results while single words worked.

**Root Cause**: The search implementation used exact phrase matching with `LIKE '%memory system test%'`, which required the exact phrase to appear in order in the content.

**Fix Applied** (`src/database/operations.ts`, line 217-258):
- Tokenized multi-word queries into individual words
- Implemented OR logic for multi-word search to find memories containing ANY of the search terms
- Single-word queries use simple LIKE matching
- Multi-word queries build dynamic SQL with OR conditions between words

**Test Results**:
- Single word "test": 6 results ✓
- Multi-word "memory system test": 7 results ✓ (was 0)
- Multi-word "episodic semantic": 2 results ✓

**Code Change**:
```typescript
// For multiple words, use OR logic to find memories containing ANY of the words
const conditions = words.map(() => '(LOWER(title) LIKE LOWER(?) OR LOWER(content) LIKE LOWER(?))').join(' OR ');
const params = words.flatMap(w => [`%${w}%`, `%${w}%`]);
```

## Issues That Were NOT Bugs

After comprehensive investigation with direct database queries, the following "issues" were found to be based on incorrect test data assumptions:

### 2. Type Corruption - FALSE ALARM

**Claimed Issue**: All retrieved memories show type as "semantic" regardless of stored value.

**Investigation Results**:
- Database correctly stores and retrieves `memory_type` field
- Test memories created with "episodic" → Retrieved as "episodic" ✓
- Test memories created with "semantic" → Retrieved as "semantic" ✓
- Old test data in database had `memory_type: "MEMORY"` (uppercase), not "episodic" or "semantic"
- The mapping function `SchemaCompatibility.mapMemoryFromDatabase()` preserves the exact database value

**Conclusion**: No corruption exists. The user's test data had uppercase "MEMORY" type, which was correctly retrieved.

### 3. Importance Corruption - FALSE ALARM

**Claimed Issue**: Importance field always returns 3 regardless of stored value (0.1-1.0).

**Investigation Results**:
- Database correctly stores and retrieves `importance` as REAL type
- Test memories with importance 0.8 → Retrieved as 0.8 ✓
- Test memories with importance 0.6 → Retrieved as 0.6 ✓
- Old test data had `importance: 3` or `importance: 5` in the database
- The database schema has DEFAULT 0.5, but stored values are preserved exactly

**Conclusion**: No corruption exists. The old test data actually had integer values 3 and 5, which were correctly retrieved.

### 4. Metadata Loss - FALSE ALARM

**Claimed Issue**: All metadata is null on retrieval despite being stored.

**Investigation Results**:
- Database correctly stores metadata as JSON strings
- Empty string `""` converts to `{}`
- Test memories with `{test: "episodic", version: "v1"}` → Retrieved correctly ✓
- Test memories with `{test: "semantic", version: "v2"}` → Retrieved correctly ✓
- Old test data had empty string `""` or `"{}"`, which correctly parses to `{}`

**Conclusion**: No loss exists. Empty/minimal metadata was correctly stored and parsed.

### 5. Date Corruption - FALSE ALARM

**Claimed Issue**: created_at shows "Invalid Date".

**Investigation Results**:
- Database stores ISO 8601 timestamps: `2025-09-30T01:49:20.876Z`
- Retrieval preserves exact timestamp strings
- All dates parse correctly with `Date.parse()` ✓

**Conclusion**: No corruption exists. Dates are stored and retrieved correctly as ISO strings.

## Enhancements Added

### Debug Logging
Added optional debug logging in `SchemaCompatibility.mapMemoryFromDatabase()` (line 103-113):
```typescript
const debugEnabled = process.env.MCP_DEBUG === '1';
if (debugEnabled) {
  console.error('[DEBUG] mapMemoryFromDatabase input:', {
    id: row.id,
    memory_type: row.memory_type,
    importance: row.importance,
    metadata: row.metadata,
    created_at: row.created_at,
  });
}
```

Enable with: `export MCP_DEBUG=1`

## Test Scripts Created

### 1. `/scripts/debug-database.ts`
Direct database inspection script that:
- Shows raw table schema
- Displays raw database values without any mapping
- Tests different search query patterns
- Compares single-word vs multi-word search results

### 2. `/scripts/test-mapping.ts`
Tests the mapping layer to verify field transformations:
- Retrieves raw database rows
- Applies mapping functions
- Compares before/after values
- Identifies any transformation issues

### 3. `/scripts/test-all-fixes.ts`
Comprehensive end-to-end test suite:
- Creates test memories with specific values
- Retrieves and verifies field preservation
- Tests multi-word search functionality
- Validates date parsing
- Reports pass/fail for each test

Run with: `npx tsx scripts/test-all-fixes.ts`

## Database Schema Notes

The production database schema (from Python migration):
- `id`: TEXT PRIMARY KEY (UUID format)
- `memory_type`: TEXT (values: episodic, semantic, procedural, fact, MEMORY, etc.)
- `importance`: REAL (0.0-1.0 for new entries, integers for old entries)
- `metadata`: TEXT (JSON string)
- `created_at`: TIMESTAMP (ISO 8601 format)

No database triggers or defaults override user-provided values - all fields are preserved exactly as stored.

## Files Modified

1. `/src/database/operations.ts` - Fixed multi-word search implementation
2. `/src/database/compatibility.ts` - Added debug logging
3. `/scripts/debug-database.ts` - Created for investigation
4. `/scripts/test-mapping.ts` - Created for testing
5. `/scripts/test-all-fixes.ts` - Created for validation

## Recommendations

1. **Data Cleanup**: Consider migrating old memories with:
   - Uppercase `MEMORY` → lowercase `episodic`/`semantic`
   - Integer importance (3, 5) → normalized float (0.8, 0.9)

2. **Search Enhancement**: Future improvements could include:
   - Full-text search ranking
   - Phrase detection (quoted strings)
   - AND vs OR mode selection
   - Search result scoring

3. **Testing**: The test scripts should be integrated into the CI/CD pipeline for regression testing.

## Summary

**Fixed**: 1 critical bug (multi-word search)
**Verified Working**: 4 features (type, importance, metadata, dates)
**Test Coverage**: Comprehensive test suite created
**Build Status**: All TypeScript compilation successful ✓