# Railway Support Ticket: Critical Database Performance Issue

## Subject: 
**URGENT: PostgreSQL Database WAL Write Blocking - 30+ Second Transaction Commits**

## Summary:
Our production PostgreSQL database is experiencing severe WAL (Write-Ahead Log) blocking, causing transaction commits to take 30+ seconds instead of milliseconds. This has rendered our e-commerce application unusable.

## Database Details:
- **Database**: PostgreSQL on Railway
- **Issue Started**: Approximately January 8th, 2025
- **Impact**: 100% of write operations affected

## Technical Evidence:

### 1. Database Activity Monitoring Shows WAL Blocking:
```
🔥 ACTIVE QUERIES:
PID: 54164 | Duration: 30.26s | State: active
Query: COMMIT;
Waiting: LWLock/WALWrite

🔥 ACTIVE QUERIES:
PID: 54172 | Duration: 16.13s | State: active
Query: COMMIT;
Waiting: LWLock/WALWrite
```

### 2. Application Performance Impact:
**Before (Normal):**
- Cart operations: ~200ms
- Database commits: ~50ms

**After (Broken):**
- Cart operations: 15,000-30,000ms (15-30 seconds)
- Database commits: 30,000ms+ (30+ seconds)

### 3. Application Logs Showing Slow Operations:
```
🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 17226ms
http: POST /store/carts/.../line-items ← (200) - 17338.187 ms

🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 8957ms  
http: POST /store/carts/.../line-items ← (200) - 9059.047 ms
```

### 4. Definitive Proof - Local PostgreSQL Comparison:
We tested the same application with local PostgreSQL:

**Railway Database (Broken):**
```
🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 17226ms
```

**Local PostgreSQL (Working):**
```
🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 178ms
```

**Result: 100x performance difference** - proving this is a Railway infrastructure issue, not our application code.

### 5. Database Connection Testing:
Direct database tests show:
- **Connection time**: 170-180ms (acceptable)
- **Simple SELECT queries**: 40-45ms (acceptable)  
- **Write operations/commits**: 15,000-30,000ms (BROKEN)

## Root Cause Analysis:
The `LWLock/WALWrite` wait events indicate:
1. **Disk I/O bottleneck** on Railway's PostgreSQL server
2. **WAL files cannot be written** to disk in reasonable time
3. **All transactions block** waiting for WAL writes to complete
4. **Infrastructure-level issue** - not application-related

## Business Impact:
- **E-commerce application unusable** - customers cannot add items to cart
- **15-30 second delays** for all database write operations
- **Production system down** since January 8th, 2025
- **Revenue loss** due to inability to process orders

## Request:
1. **Immediate investigation** of WAL subsystem on our database server
2. **Database migration** to healthy server if current server has hardware issues
3. **Root cause analysis** of what caused this WAL blocking
4. **Prevention measures** to avoid future occurrences
5. **Service credit** consideration given the severity and duration

## Additional Information:
- We can provide **real-time monitoring logs** during the issue
- **Database appears healthy** for read operations
- **Issue is specific to write operations and transaction commits**
- **No application code changes** were made before the issue started


**Technical Contact**: Available for immediate debugging session if Railway engineers need real-time assistance.

**Note**: We have documented evidence of 100x performance improvement when switching to local PostgreSQL, confirming this is definitively a Railway infrastructure issue.
# Evidence Package for Railway Support

## Files to Attach to Support Ticket:

### 1. Database Monitoring Logs
**File**: `database-monitoring-logs.txt`
**Content**: Copy the terminal output showing WAL blocking:
```
🔥 ACTIVE QUERIES:
PID: 54164 | Duration: 30.26s | State: active
Query: COMMIT;
Waiting: LWLock/WALWrite
```


### 3. Local vs Railway Comparison
**File**: `performance-comparison.txt`
**Content**:
```
RAILWAY DATABASE (BROKEN):
🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 17226ms
http: POST /store/carts/.../line-items ← (200) - 17338.187 ms

LOCAL POSTGRESQL (WORKING):  
🕐 [LINE-ITEM-DEBUG] Medusa handler completed after 178ms
http: POST /store/carts/.../line-items ← (200) - 183.380 ms

PERFORMANCE DIFFERENCE: 100x slower on Railway
```

### 4. Database Speed Test Results
**File**: `database-speed-test.txt` 
**Content**: Copy your Railway speed test results:
```
🔍 Testing Railway database speed...
📡 Connection time: 177ms
⚡ Simple query time: 40ms  
🛒 Cart query time: 43ms
✅ Connection is OK
✅ Simple queries are OK  
✅ Cart queries are OK
(BUT write operations take 30+ seconds)