I'd like to hear from JCrespo as to whether this is needed or desirable. I'm skeptical that access patterns will actually make sharding by page ID more efficient.
The proposed "slot history" would potentially be more efficient if the slot table were sharded by page ID, since it will be having to join that table to hit the
slot_inherited field. Even without sharding, I suppose the DB could select on
slot_page, slot_inherited rather than using
rev_page then filtering based on the join.
I can't think of any common situation where sharding the content table by page ID would be more efficient. Nor can I think of a situation where we'd want to use
content_page directly in a query.