Found in T243915, For example, [[https://performance.wikimedia.org/xhgui/run/symbol?id=5e31dfb93f3dfab12dff839f&symbol=Wikibase%5CRdf%5CRdfBuilder%3A%3AresolveMentionedEntities|RDF output of Q7251, loads 252 other entities]] called from `Wikibase\Rdf\RdfBuilder::resolveMentionedEntities`. This wouldn't scale, most of the time responding for RDF is being spent on loading those, not to mention the huge memory footprint caused by it. the entities are in ExternalStorage, so loading can't be batched (due to the nature of ES using consistent hashing), the I/O needed for it is crazy while it doesn't need all of the other entities, it only needs labels, property info, and statements like "formatter url" that can be also put in some cache here and there. After talking to devs and PM, it doesn't seem to be intentional.