test.js

const { types, Client, Pool } = require('pg');
const Knex = require('knex');

const knex = new Knex({
  client: 'pg',
  connection: 'postgresql://localhost/postgres',
});

const benchmark = async (fn, num) => {
  const start = new Date().getTime();
  await Promise.all(Array(num).fill(fn()));
  const ms = new Date().getTime() - start;
  console.log(`${num} took ${ms}ms`);
};

(async () => {
  await knex.transaction(async trx => {
    const fn = () => trx.raw('select 1');
    await benchmark(fn, 1000);
  });

  const pool = new Pool({
    database: 'postgres',
  });

  const client = await pool.connect();
  const fn = () => client.query('select 1');
  await benchmark(fn, 1000);
})();

try to see result of select random() instead of select 1, re-write this code and you'll find that result of both benchmarks are almost the same