'use strict';

const {MongoClient} = require('mongodb');

const sleep = ms => new Promise(r => setTimeout(r, ms));

(async () => {
  const client = await MongoClient.connect('mongodb://localhost:27017/?replSet=rs', { monitorCommands: true });
  client.on('commandStarted', e => console.log(JSON.stringify(e.command)));

  const collection = client.db('test').collection('test');

  const count = await collection.count();

  console.log(count);

  console.log('querying');
  const time = process.hrtime()
  const cursor = collection.find({}).batchSize(1);
  try {
    for (let i = 0; i < 100000; i++) {
      await cursor.next();
      await sleep(1000);
    }

  } catch (e) {
    console.error(e);
  }

  console.log('shutting down');
  console.log(process.hrtime(time));
  await cursor.close();
  await client.close();
  console.log('done');
  process.exit(0);
})();