# Data Quality Analysis Report
**Database**: mcp-memory-ts (Turso/LibSQL)
**Date**: 2025-10-14
**Total Memories**: 875
**Analysis Tool**: `scripts/analyze-data-quality.ts`
---
## Executive Summary
Analysis of the mcp-memory-ts database identified **two significant data quality issues** affecting 716 records (81.8% of database):
1. **Empty Content Memories**: 20 records (2.3%) with null/empty content
2. **Duplicate Groups**: 75 groups containing 696 duplicate records (79.5%)
Both issues are **safe to clean up** with low risk of data loss. The cleanup will preserve 159 unique memories with valid content.
---
## Issue 1: Empty Content Memories
### Overview
- **Records Found**: 20 memories
- **Percentage**: 2.3% of database
- **Risk Level**: ⚠️ **LOW** (with corruption detected)
### Pattern Analysis
**Distribution by User:**
- `test@example.com`: 3 memories (15%)
- `756e8675-9783-42ad-a859-cd51f331e46c`: 17 memories (85%)
**Distribution by Date:**
- `2025-10-08`: 5 memories
- `2025-10-09`: 12 memories
- `2025-10-14`: 3 memories
**Content Characteristics:**
| Characteristic | Count | Percentage |
|---------------|-------|------------|
| With embeddings | 17 | 85.0% |
| With valid embeddings (1536 dims) | 17 | 85.0% |
| With metadata | 0 | 0.0% |
| With title | 20 | 100.0% |
| With tags | 0 | 0.0% |
### Key Findings
1. **Data Corruption Detected**: 17 of 20 empty memories have OpenAI embeddings (1536 dimensions)
- Embeddings should NOT exist without content
- Indicates data integrity issue or API bug
- 3 memories have empty embeddings (0 dimensions) - likely from test user
2. **Generic Titles**: All 20 memories have identical title "Memory"
- No descriptive information
- Suggests automated test data or failed creation
3. **No Valuable Metadata**:
- Zero metadata entries
- Zero tags
- No entity relationships
4. **Recent Creation**: Most created October 8-9, 2025
- Concentrated time period suggests specific incident
- Possibly from test suite or API integration issues
### Example Record
```json
{
"id": "8b593c3d-0514-412b-a5b5-b0250b225f3a",
"user_id": "756e8675-9783-42ad-a859-cd51f331e46c",
"title": "Memory",
"content": "", // ❌ EMPTY
"memory_type": "semantic",
"importance": 0.5,
"tags": [],
"metadata": {},
"embedding": "[...1536 dimensions...]", // ⚠️ Should not exist!
"created_at": "2025-10-09T00:44:04.369Z",
"updated_at": "2025-10-10 00:32:01"
}
```
### Root Cause Analysis
**Likely causes:**
1. **API Integration Bug**: Memory creation succeeded but content field not populated
2. **Test Data**: Automated tests creating placeholder records
3. **Embedding Monitor**: Background process updated embeddings despite empty content
4. **Database Migration**: Schema changes may have cleared content fields
**Evidence points to**: Test data from integration/E2E tests based on:
- Generic "Memory" titles
- Concentrated creation period
- No metadata or tags
- Mix of users (test@example.com and UUID user)
### Recommendation
**Action**: ✅ **DELETE ALL 20 RECORDS**
**Justification:**
- ❌ No valuable content to preserve
- ❌ No metadata or tags
- ❌ Data corruption present (embeddings without content)
- ✅ All appear to be test data or failed creations
- ✅ Low risk - no user-facing impact
**SQL Command:**
```sql
DELETE FROM memories
WHERE content IS NULL OR TRIM(content) = '';
```
---
## Issue 2: Duplicate Memory Groups
### Overview
- **Duplicate Groups**: 75 groups
- **Total Duplicates**: 696 records (keeping 1 per group)
- **Percentage**: 79.5% of database
- **Risk Level**: ✅ **LOW** (safe deduplication)
### Pattern Analysis
**Distribution by User:**
- `756e8675-9783-42ad-a859-cd51f331e46c`: 75 groups (100%)
- All duplicates are same user + same content
**Distribution by Memory Type:**
- `semantic`: 74 groups (98.7%)
- `episodic`: 1 group (1.3%)
**Timing Patterns:**
- Quick succession (<1 min): 0 groups
- Same day: 75 groups (100%)
- Time span: Most duplicates created over ~199 minutes (~3.3 hours)
- Date range: October 8-9, 2025
### Top Duplicate Groups
| Rank | Duplicates | Content Preview | Type | Time Span |
|------|------------|-----------------|------|-----------|
| 1 | 67 | "Test content" | semantic | 206 minutes |
| 2 | 19 | "E2E test memory content" | semantic | 198 minutes |
| 3 | 17 | "Memory leak test 2" | semantic | 199 minutes |
| 4 | 17 | "Memory leak test 1" | semantic | 199 minutes |
| 5 | 17 | "Memory leak test 0" | semantic | 199 minutes |
| 6 | 17 | "AAAA..." (100 chars) | semantic | 199 minutes |
| 7 | 17 | "Memory 3" | semantic | 199 minutes |
| 8 | 17 | "Memory 2" | semantic | 199 minutes |
| 9 | 17 | "Memory 1" | semantic | 199 minutes |
| 10 | 17 | "Concurrent test memory 4" | semantic | 199 minutes |
### Key Findings
1. **Test Data Dominance**: Content clearly indicates test/development data
- "Test content" (67 duplicates!)
- "E2E test memory content"
- "Memory leak test X"
- "Concurrent test memory X"
- "Integration test memory"
2. **Single User Impact**: 100% of duplicates belong to ONE user
- User ID: `756e8675-9783-42ad-a859-cd51f331e46c`
- Suggests development/testing environment data
3. **Systematic Duplication**: Consistent patterns suggest automated process
- Same content repeated 16-67 times
- Created over 3-hour window
- Sequential creation (not simultaneous)
4. **Not User Error**: Time spans rule out accidental double-clicks
- Duplicates created over hours, not seconds
- Systematic pattern indicates automation
### Example Duplicate Group
**Content**: "Test content"
**Duplicates**: 67 records
**User**: `756e8675-9783-42ad-a859-cd51f331e46c`
**Type**: semantic
**First Created**: `2025-10-08T21:18:36.741Z`
**Last Created**: `2025-10-09T00:44:52.516Z`
**Time Span**: 206 minutes (3.4 hours)
**Sample IDs**: c436d85e-9649-4094-a35b-15d5e8ba4ea1, 39e32dc6-caf1-442f-bf3e-789f2ffda8cb, ...
### Root Cause Analysis
**Likely causes:**
1. **Test Suite Bug**: Tests not cleaning up after execution
2. **Memory Leak Tests**: Ironically, the "memory leak test" memories are leaking!
3. **Concurrent Test Failures**: Tests creating multiple instances without proper isolation
4. **Development Environment**: Test data from local development/CI runs
**Evidence points to**: Test suite pollution based on:
- Test-specific content ("E2E test", "Memory leak test", "Concurrent test")
- Single development user
- Concentrated time period
- Systematic repetition patterns
### Recommendation
**Action**: ✅ **DEDUPLICATE - KEEP OLDEST**
**Strategy:**
1. Keep the **oldest record** (MIN(created_at)) per duplicate group
2. Delete newer duplicates with same content + same user
3. Preserve entity relationships and metadata from kept record
**Justification:**
- ✅ No data loss (keeping one copy of each unique content)
- ✅ All duplicates are same user + exact content match
- ✅ Test data - not production user data
- ✅ Oldest record preserves original creation timestamp
- ⚠️ Should verify metadata/tags don't differ between duplicates
**SQL Command:**
```sql
-- Keep oldest, delete newer duplicates
DELETE FROM memories
WHERE id IN (
SELECT m2.id
FROM memories m1
INNER JOIN memories m2
ON m1.content = m2.content
AND m1.user_id = m2.user_id
AND m1.created_at < m2.created_at
WHERE m1.content IS NOT NULL
AND TRIM(m1.content) != ''
);
```
---
## Risk Assessment
### Overall Risk Level: ✅ **LOW**
| Factor | Assessment | Details |
|--------|-----------|---------|
| **Data Loss** | ✅ Minimal | Only removing empty/duplicate records |
| **User Impact** | ✅ None | Primarily test data, single dev user |
| **Reversibility** | ✅ High | Backup table created before cleanup |
| **Corruption Risk** | ⚠️ Low | Some embeddings without content detected |
| **Business Impact** | ✅ None | Test environment data |
### Safety Measures
1. ✅ **Backup Created**: Full `memories_backup_20251014` table
2. ✅ **Preview Queries**: Dry-run queries show exactly what will be deleted
3. ✅ **Verification Steps**: Post-cleanup validation queries
4. ✅ **Rollback Plan**: Simple restore from backup if needed
---
## Cleanup Execution Plan
### Phase 1: Preparation ✅
1. Create full backup table: `memories_backup_20251014`
2. Verify backup record count matches source
3. Review analysis report (this document)
### Phase 2: Execution 🔧
**Step 1**: Delete empty content memories
```sql
DELETE FROM memories
WHERE content IS NULL OR TRIM(content) = '';
```
- Expected deletions: **20 records**
- Expected time: <1 second
**Step 2**: Deduplicate memories
```sql
DELETE FROM memories
WHERE id IN (
SELECT m2.id
FROM memories m1
INNER JOIN memories m2
ON m1.content = m2.content
AND m1.user_id = m2.user_id
AND m1.created_at < m2.created_at
WHERE m1.content IS NOT NULL
AND TRIM(m1.content) != ''
);
```
- Expected deletions: **696 records**
- Expected time: <5 seconds
### Phase 3: Verification ✅
**Verify cleanup success:**
```sql
-- Should return 0
SELECT COUNT(*) FROM memories
WHERE content IS NULL OR TRIM(content) = '';
-- Should return 0
SELECT COUNT(*) - COUNT(DISTINCT content || user_id)
FROM memories
WHERE content IS NOT NULL AND TRIM(content) != '';
-- Final count should be ~159
SELECT COUNT(*) FROM memories;
```
### Phase 4: Monitoring 📊
After cleanup, monitor for:
1. **Application Errors**: Check MCP server logs
2. **User Reports**: Monitor for missing memory complaints
3. **Database Health**: Run health check script
4. **Embedding Coverage**: Verify 100% coverage maintained
---
## Expected Results
### Before Cleanup
| Metric | Value | Percentage |
|--------|-------|------------|
| Total memories | 875 | 100% |
| Empty content | 20 | 2.3% |
| Duplicate groups | 75 | - |
| Duplicate records | 696 | 79.5% |
| Unique valid memories | 159 | 18.2% |
### After Cleanup
| Metric | Value | Percentage |
|--------|-------|------------|
| Total memories | 159 | 100% |
| Empty content | 0 | 0% |
| Duplicate groups | 0 | - |
| Duplicate records | 0 | 0% |
| Unique valid memories | 159 | 100% |
### Impact Summary
- **Records Preserved**: 159 unique memories
- **Records Deleted**: 716 (81.8% of database)
- Empty content: 20
- Duplicates: 696
- **Database Size Reduction**: ~81.8%
- **Data Quality Improvement**: 100% unique, valid content
---
## Rollback Procedure
If issues arise after cleanup:
```sql
-- 1. Restore from backup
DELETE FROM memories;
INSERT INTO memories SELECT * FROM memories_backup_20251014;
-- 2. Verify restoration
SELECT COUNT(*) as restored FROM memories;
SELECT COUNT(*) as backup FROM memories_backup_20251014;
-- Should match: 875 records
```
---
## Prevention Recommendations
To prevent future data quality issues:
### 1. Test Data Cleanup
- ✅ Add teardown methods to test suites
- ✅ Use separate test database or namespace
- ✅ Implement test data expiration (auto-delete after 24h)
- ✅ Add CI checks for test data leakage
### 2. Content Validation
- ✅ Add database constraint: `CHECK (TRIM(content) != '')`
- ✅ Validate content before creating embeddings
- ✅ Add application-level validation
- ✅ Implement content length minimum (e.g., 3 characters)
### 3. Duplicate Prevention
- ✅ Add unique constraint: `UNIQUE(user_id, content, created_at)`
- ✅ Implement client-side deduplication
- ✅ Add idempotency keys to API
- ✅ Rate limit memory creation per user
### 4. Monitoring
- ✅ Add data quality health checks to CI/CD
- ✅ Alert on empty content creation
- ✅ Monitor duplicate creation rate
- ✅ Dashboard for database metrics
### 5. Embedding Integrity
- ✅ Never generate embeddings for empty content
- ✅ Validate content exists before embedding monitor runs
- ✅ Add pre-check to embedding generation
- ✅ Log warnings for skipped embeddings
---
## Files Generated
1. **Analysis Script**: `/Users/masa/Projects/mcp-memory-ts/scripts/analyze-data-quality.ts`
- Queries database for empty content and duplicates
- Generates detailed pattern analysis
- Provides recommendations
2. **Cleanup SQL**: `/Users/masa/Projects/mcp-memory-ts/scripts/cleanup-data-quality.sql`
- Complete cleanup procedure with safety measures
- Backup creation
- Verification queries
- Rollback instructions
3. **This Report**: `/Users/masa/Projects/mcp-memory-ts/DATA_QUALITY_ANALYSIS.md`
- Comprehensive analysis
- Risk assessment
- Execution plan
---
## Execution Commands
To run the cleanup:
```bash
# 1. Run analysis (review output)
npx tsx scripts/analyze-data-quality.ts
# 2. Execute cleanup (via database client)
# Copy SQL from scripts/cleanup-data-quality.sql
# Execute step-by-step, verifying each step
# 3. Verify results
npm run health-check # If health check script exists
```
---
## Conclusion
The mcp-memory-ts database contains significant test data pollution (81.8%) that should be cleaned up. Both identified issues are:
✅ **Safe to clean** - primarily test data
✅ **Low risk** - backups and rollback available
✅ **High benefit** - 81.8% database size reduction
✅ **Preserves data** - keeping all unique valid memories
**Recommendation**: **Proceed with cleanup** following the execution plan above.
---
**Report Generated**: 2025-10-14
**Analyst**: Claude Code (Research Agent)
**Tool Version**: analyze-data-quality.ts v1.0.0
