/**
* @param LoadBalancer $dbLoadBalancer A load balancer for acquiring database connections
- * @param WANObjectCache $cache A cache manager for caching blobs
+ * @param WANObjectCache $cache A cache manager for caching blobs. This can be the local
+ * wiki's default instance even if $wikiId refers to a different wiki, since
+ * makeGlobalKey() is used to constructed a key that allows cached blobs from the
+ * same database to be re-used between wikis. For example, enwiki and frwiki will
+ * use the same cache keys for blobs from the wikidatawiki database, regardless of
+ * the cache's default key space.
* @param bool|string $wikiId The ID of the target wiki database. Use false for the local wiki.
*/
public function __construct(