institutional-trader/README/CONNECTION_STRING_FIX.md

Fix: ENOTFOUND Database Hostname Error

Problem

You're seeing: ENOTFOUND db.mycttyevrycmkhlvwgfk.supabase.co

This means the hostname cannot be resolved. Common causes:

1. Project is paused in Supabase
2. Using wrong connection string format
3. Need to use Pooler connection instead

Solution 1: Use Connection Pooler (RECOMMENDED)

Supabase provides a connection pooler that's more reliable:

1. Go to Supabase Dashboard → Settings → Database

2. Find "Connection Pooling" section

3. Select "Transaction" mode (or "Session" if you need transactions)

4. Copy the connection string - it will look like:

   postgresql://postgres:[YOUR-PASSWORD]@mycttyevrycmkhlvwgfk.pooler.supabase.com:6543/postgres
   

   OR

   postgresql://postgres:[YOUR-PASSWORD]@mycttyevrycmkhlvwgfk.pooler.supabase.com:5432/postgres
   

5. Update your .env file:

   DATABASE_URL=postgresql://postgres:your_password@mycttyevrycmkhlvwgfk.pooler.supabase.com:6543/postgres
   

Key differences:

• Uses .pooler.supabase.com instead of db.xxx.supabase.co
• Port is usually 6543 (transaction mode) or 5432 (session mode)
• More reliable for serverless/cloud deployments

Solution 2: Check Project Status

1. Go to Supabase Dashboard
2. Check if your project shows as "Paused" or "Inactive"
3. If paused, click "Restore" to reactivate it
4. Wait a few minutes for DNS to propagate
5. Try connecting again

Solution 3: Use Supabase Client Instead

If direct connection doesn't work, use Supabase client:

1. Get your API keys:

   • Go to Supabase Dashboard → Settings → API
   • Copy:
     • Project URL: https://mycttyevrycmkhlvwgfk.supabase.co
     • service_role key (secret)

2. Update your .env file:

   # Remove or comment out DATABASE_URL
   # DATABASE_URL=...
   
   # Add Supabase client config
   SUPABASE_URL=https://mycttyevrycmkhlvwgfk.supabase.co
   SUPABASE_SERVICE_KEY=your_service_role_key_here
   

3. Restart server

Solution 4: Verify Connection String Format

Make sure your connection string has the correct format:

Direct connection (if project is active):

postgresql://postgres:password@db.project-ref.supabase.co:5432/postgres

Pooler connection (recommended):

postgresql://postgres:password@project-ref.pooler.supabase.com:6543/postgres

Common mistakes:

• ❌ Missing postgresql:// prefix
• ❌ Wrong port (should be 5432 or 6543)
• ❌ Missing password brackets [password] should be replaced with actual password
• ❌ Using db. prefix with pooler (pooler doesn't use db.)

Quick Test

After updating your .env file, test the connection:

cd backend
npm run dev

You should see:

✅ Database connection successful (PostgreSQL direct)

Or:

✅ Database connection successful (Supabase)

Still Not Working?

1. Check your network/firewall - Make sure port 5432 or 6543 is not blocked
2. Try pinging the hostname:

   ping mycttyevrycmkhlvwgfk.pooler.supabase.com
   

3. Verify project is active in Supabase Dashboard
4. Check Supabase status page for any outages
5. Contact Supabase support if project appears active but connection fails