We should check whether it's possible to move wbc_entity_usage to an own database shard, away from the main wiki databases.
- There might be places where the information is currently being JOINed against the other tables (API query modules?), we need to look into that and see how hard it would be to do that programmatically.
- How many writes are currently happening on the tables? Can that (plus an order of magnitude?) more easily be sustained if the tables are separate from the main wiki databases?
Question 1. is for the Wikidata team to answer, while 2. probably needs to be answered by a DBA.