How to fix P6000: Server cannot be reached (Pulse) in Prisma

# PostgreSQL example - verify all components
postgresql://username:password@hostname:5432/database?sslmode=require

# Common issues:
# - Wrong hostname (use FQDN, not localhost)
# - Wrong port (PostgreSQL default 5432, MySQL 3306)
# - Missing or incorrect password
# - Database name typo
# - Special characters in password not URL-encoded

# PostgreSQL test
psql postgresql://username:password@hostname:5432/database

# If connection works here but not in Pulse, the issue is specific to Pulse's access

# Supabase - use the public hostname provided in settings
postgresql://user:password@db.supabase.co:5432/postgres

# Railway - verify the public domain is enabled
postgresql://user:password@railway-app-prod.railway.app:5432/postgres

# AWS RDS - use the publicly accessible endpoint
postgresql://user:password@mydb.c9akciq32.us-east-1.rds.amazonaws.com:5432/postgres

// Pulse currently does NOT support self-signed certificates well
// If using a self-signed cert, try disabling SSL verification:
// DATABASE_URL=postgresql://...?sslmode=disable

// However, this is not recommended for production
// Better approach: use `sslmode=require` with a valid certificate
// DATABASE_URL=postgresql://...?sslmode=require

# Test certificate validity
openssl s_client -connect hostname:5432

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function testConnection() {
  try {
    // Test 1: Regular Prisma ORM works
    const result = await prisma.$queryRaw`SELECT 1`;
    console.log('✓ Prisma ORM connection works:', result);
  } catch (error) {
    console.error('✗ Prisma ORM connection failed:', error);
    return;
  }

  try {
    // Test 2: Pulse subscription can connect
    const subscription = await prisma.user.subscribe({
      create: { after: true }
    });
    console.log('✓ Pulse subscription works');
    subscription.stop();
  } catch (error: any) {
    console.error('✗ Pulse subscription failed:', error.message);
  }

  await prisma.$disconnect();
}

testConnection();

# For cloud databases, check the provider's dashboard:
# - Supabase: Check project status and uptime
# - Railway: Verify service is running
# - PlanetScale: Check server status and connection status
# - AWS RDS: Check instance status in AWS Console

# For self-hosted:
# Check if the database process is running
systemctl status postgresql

# Check disk space (database needs space to accept connections)
df -h

# Check if database is accepting connections
# Try connecting with a database client

# Check database logs for errors
tail -f /var/log/postgresql/postgresql.log

# Check that DATABASE_URL is available in your environment
echo $DATABASE_URL

# For Vercel/Railway/other platforms, verify the variable is set in deployment settings
# This is often a common source of P6000 errors in production

# For local development, ensure .env or .env.local has:
DATABASE_URL=postgresql://username:password@host:port/database?sslmode=require

# Do not commit .env files with credentials to git
echo ".env.local" >> .gitignore

# Test network connectivity to the database host
telnet hostname 5432

# Or with nc (nc might not be available, but telnet usually is)
nc -zv hostname 5432

# Try from your deployment platform environment
# (e.g., SSH into a Vercel function, Railway container, etc.)