hardPerformanceNext.js

The connection exhaustion

A developer asked an AI assistant to add a database query to a Next.js API route. The suggested code works fine in local testing, but under real traffic the app starts throwing 'too many connections' errors and the database eventually stops responding.

route.ts

import { Client } from 'pg';

export async function GET(request: Request) {
  const client = new Client({ connectionString: process.env.DATABASE_URL });
  await client.connect();
  const result = await client.query('SELECT * FROM products LIMIT 20');
  return Response.json(result.rows);
}

Why does this route work fine in local testing but crash the database under real traffic?

SELECT * always locks the entire products table until the request completes.

process.env.DATABASE_URL is re-read from disk on every request, adding latency but no connection issue.

A new client connects to the database on every request and is never explicitly closed or reused. Under concurrent traffic this quickly exhausts the database's max connection limit.

Response.json() keeps the database connection open until the client's browser tab closes.