pg version 8.7.1 hangs on await db.end() but before version 8 doesn't

The node-postgres module frequently hangs when the PostgreSQL server restarts abruptly. The node-postgres package was working fine prior to pg version 8.7.1 as required by Node.js version 16. The two positions marked A and B represents when a disconnect from the database could be experienced. The db.end() API hangs on the await in the bad case. Commenting out the await avoids the hang.

let db = null;

try {
  db = new pg.Client({...});
  await db.connect();
  // Position A
  await db.query("<SQL query>");
  // Position B
} finally {
  if (db) {
//    await db.end(); // the await can hang indefinitely
    db.end(); // workaround fix
  }
}

The Client.end() routine has a new implementation. Could someone check the logic to guarantee the Client.end() returned promise always resolves.

The two related issues are:

1. https://github.com/brianc/node-postgres/issues/2329
2. https://github.com/brianc/node-postgres/issues/2341

[alfreema]

I was having this issue when using jest to do some integration testing. That lead down a rabbit-hole that solved a bunch of problems including the ability to get pool.end() working properly.

By treating “new Pool()” as a promise, it cleaned my whole mess up:

async function createPool () {
  return await new Pool({ connectionString })
}

and all of the issues with closing clients, pools, etc completely went away just by awaiting “new Pool(…)”. Maybe new Pool needs a Process.nextTick( … ) somewhere? I’m clueless, but hopefully this is a clue to help the brainiacs figure out the underlying problem.

[snowbldr]

@alfreema I had this same issue. I tried adding await to the new Pool call, and can confirm it did fix it for me. Thanks a bunch for the work around 👍