/**
	 * @since 1.27
	 * @param WANObjectCache $cache
	 * @return string
	 */
	protected function getCacheKey( WANObjectCache $cache ) {
		$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
		$lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();

		return $cache->makeGlobalKey( 'user', 'id', $lbFactory->getLocalDomainID(), $this->mId );
	}