CounterService::addCollection

public function addCollection(MessageCollection $messages, Relation $relation): void
{
	$insertFields = [];

	foreach ($messages as $message)
	{
		if ($relation->getMessageType() !== IM_MESSAGE_SYSTEM && $message->getAuthorId() === $relation->getUserId())
		{
			continue;
		}

		$insertFields[] = $this->prepareInsertFields($message, $relation);
	}

	MessageUnreadTable::multiplyInsertWithoutDuplicate($insertFields);
	static::clearCache($relation->getUserId());
}