We load full entities for the onLinkBegin hook handler in Wikibase Repo in order to get a label.
e.g. for each item or property on Special:Allpages, we load the entity to get the label.
a term lookup, with caching and all, should be used instead.
LinkBegin is also used in places like Special:Watchlist (i think), so if someone has a gigantic watchlist, it probably will timeout.
Whiteboard: u=dev c=backend p=8 s=2014-11-11