livedash-node/docs/neon-database-optimization.md

Neon Database Optimization Guide

This document provides specific recommendations for optimizing database connections when using Neon PostgreSQL.

Current Issues Observed

From your logs, we can see:

Can't reach database server at `ep-tiny-math-a2zsshve-pooler.eu-central-1.aws.neon.tech:5432`
[NODE-CRON] [WARN] missed execution at Sun Jun 29 2025 12:00:00 GMT+0200! Possible blocking IO or high CPU

Root Causes

1. Neon Connection Limits

• Free Tier: 20 concurrent connections
• Pro Tier: 100 concurrent connections
• Multiple schedulers can quickly exhaust connections

2. Connection Pooling Issues

• Each scheduler was creating separate PrismaClient instances
• No connection reuse between operations
• No retry logic for temporary failures

3. Neon-Specific Challenges

• Auto-pause: Databases pause after inactivity
• Cold starts: First connection after pause takes longer
• Regional latency: eu-central-1 may have variable latency

Solutions Implemented

1. Fixed Multiple PrismaClient Instances ✅

// Before: Each file created its own client
const prisma = new PrismaClient(); // ❌

// After: All use singleton
import { prisma } from "./prisma.js"; // ✅

2. Added Connection Retry Logic ✅

// Automatic retry for connection errors
await withRetry(
  async () => await databaseOperation(),
  {
    maxRetries: 3,
    initialDelay: 2000,
    maxDelay: 10000,
    backoffMultiplier: 2,
  }
);

3. Enhanced Connection Pooling ✅

// Production-ready pooling with @prisma/adapter-pg
USE_ENHANCED_POOLING=true
DATABASE_CONNECTION_LIMIT=20
DATABASE_POOL_TIMEOUT=10

Neon-Specific Configuration

Environment Variables

# Optimized for Neon
DATABASE_URL="postgresql://user:pass@ep-tiny-math-a2zsshve-pooler.eu-central-1.aws.neon.tech:5432/db?sslmode=require&connection_limit=15"

# Connection pooling (leave some headroom for manual connections)
DATABASE_CONNECTION_LIMIT=15  # Below Neon's 20 limit
DATABASE_POOL_TIMEOUT=30      # Longer timeout for cold starts
USE_ENHANCED_POOLING=true     # Enable for better resource management

# Scheduler intervals (reduce frequency to avoid overwhelming)
CSV_IMPORT_INTERVAL="*/30 * * * *"    # Every 30 minutes instead of 15
IMPORT_PROCESSING_INTERVAL="*/10 * * * *"  # Every 10 minutes instead of 5
SESSION_PROCESSING_INTERVAL="0 */2 * * *"  # Every 2 hours instead of 1

Connection String Optimization

# Add these parameters to your DATABASE_URL
?sslmode=require                    # Required for Neon
&connection_limit=15                # Explicit limit
&pool_timeout=30                    # Connection timeout
&connect_timeout=10                 # Initial connection timeout
&application_name=livedash-scheduler # For monitoring

Monitoring & Troubleshooting

1. Health Check Endpoint

# Check connection health
curl -H "Authorization: Bearer your-token" \
     http://localhost:3000/api/admin/database-health

2. Neon Dashboard Monitoring

• Monitor "Active connections" in Neon dashboard
• Check for connection spikes during scheduler runs
• Review query performance and slow queries

3. Application Logs

# Look for connection patterns
grep "Database connection" logs/*.log
grep "pool" logs/*.log
grep "retry" logs/*.log

Performance Optimizations

1. Reduce Scheduler Frequency

// Current intervals may be too aggressive
CSV_IMPORT_INTERVAL="*/15 * * * *"     // ➜ "*/30 * * * *"
IMPORT_PROCESSING_INTERVAL="*/5 * * * *"  // ➜ "*/10 * * * *"  
SESSION_PROCESSING_INTERVAL="0 * * * *"   // ➜ "0 */2 * * *"

2. Batch Size Optimization

// Reduce batch sizes to avoid long-running transactions
CSV_IMPORT_BATCH_SIZE=50         // ➜ 25
IMPORT_PROCESSING_BATCH_SIZE=50  // ➜ 25
SESSION_PROCESSING_BATCH_SIZE=20 // ➜ 10

3. Connection Keepalive

// Keep connections warm to avoid cold starts
const prisma = new PrismaClient({
  datasources: {
    db: {
      url: process.env.DATABASE_URL + "&keepalive=true"
    }
  }
});

Troubleshooting Common Issues

"Can't reach database server"

Causes:

• Neon database auto-paused
• Connection limit exceeded
• Network issues

Solutions:

1. Enable enhanced pooling: USE_ENHANCED_POOLING=true
2. Reduce connection limit: DATABASE_CONNECTION_LIMIT=15
3. Implement retry logic (already done)
4. Check Neon dashboard for database status

"Connection terminated"

Causes:

• Idle connection timeout
• Neon maintenance
• Long-running transactions

Solutions:

1. Increase pool timeout: DATABASE_POOL_TIMEOUT=30
2. Add connection cycling
3. Break large operations into smaller batches

"Missed cron execution"

Causes:

• Blocking database operations
• Scheduler overlap
• High CPU usage

Solutions:

1. Reduce scheduler frequency
2. Add concurrency limits
3. Monitor scheduler execution time

Recommended Production Settings

For Neon Free Tier (20 connections)

DATABASE_CONNECTION_LIMIT=15
DATABASE_POOL_TIMEOUT=30
USE_ENHANCED_POOLING=true
CSV_IMPORT_INTERVAL="*/30 * * * *"
IMPORT_PROCESSING_INTERVAL="*/15 * * * *"
SESSION_PROCESSING_INTERVAL="0 */3 * * *"

For Neon Pro Tier (100 connections)

DATABASE_CONNECTION_LIMIT=50
DATABASE_POOL_TIMEOUT=20
USE_ENHANCED_POOLING=true
CSV_IMPORT_INTERVAL="*/15 * * * *"
IMPORT_PROCESSING_INTERVAL="*/10 * * * *"
SESSION_PROCESSING_INTERVAL="0 */2 * * *"

Next Steps

1. Immediate: Apply the new environment variables
2. Short-term: Monitor connection usage via health endpoint
3. Long-term: Consider upgrading to Neon Pro for more connections
4. Optional: Implement read replicas for analytics queries

Monitoring Checklist

• Check Neon dashboard for connection spikes
• Monitor scheduler execution times
• Review error logs for connection patterns
• Test health endpoint regularly
• Set up alerts for connection failures

With these optimizations, your Neon database connections should be much more stable and efficient!