AbstractThreadStrategy::checkThreads

public function checkThreads(): ?int
{
	$thread = PostingThreadTable::getList(
		[
			"select" => ["THREAD_ID"],
			"filter" => [
				'=POSTING_ID' => $this->postingId,
			],
			"limit"  => 1
		]
	)->fetchAll();

	if (isset($thread[0]) && isset($thread[0]["THREAD_ID"]))
	{
		return self::THREAD_UNAVAILABLE;
	}

	return self::THREAD_NEEDED;
}