PostgreSQL LISTEN NOTIFY support

Instead of db query each timeout seconds

my sux version

<?php

namespace application\modules\queue\components\drivers;

use yii\queue\db\Queue;

class Db extends Queue
{

	public $listener = 'queue';

	public function run($repeat, $timeout = 0)
	{
		if(!$repeat) {
			return parent::run($repeat, $timeout);
		}
		$this->db->createCommand("LISTEN {$this->listener}")->execute();
		return $this->runWorker(function (callable $canContinue) use ($repeat, $timeout) {
			$first = true;
			while($canContinue()) {
				if(!$first) {
					$notify = $this->db->pdo->pgsqlGetNotify();
					if(!$notify) {
						sleep($timeout);
						continue;
					}
				}
				$first = false;
				while(true) {
					if ($payload = $this->reserve() and $this->handleMessage(
						$payload['id'],
						$payload['job'],
						$payload['ttr'],
						$payload['attempt']
					)) {
						$this->release($payload);
						continue;
					}
					break;
				}
			}
		});
	}

	public function push($job)
	{
		$id = parent::push($job);
		$this->notify($id);
		return $id;
	}

	public function notify($payload)
	{
		$payload = serialize($payload);
		$this->db->createCommand("NOTIFY {$this->listener}, '$payload'")->execute();
	}

}

Start with the PHP example in the issue and compare its LISTEN/NOTIFY flow with the repository's existing database queue worker and polling behavior. Define how PostgreSQL notification support should interact with repeated workers, job pushing, and payload delivery; done should mean the database queue can react to notifications without polling delays.