One "fix" I could imagine for this would be for the Wiki Replicas to
also provide per-entity views of the comment table that only return
rows related to a single entity table. For example a
"comment_ipblocks" view could use a where clause specific to the
ipblocks entity table like "WHERE exists( select 1 from ipblocks where
ipb_reason_id = comment_id and ipb_deleted = 0)" and exclude the tests
for other entities (image, filearchive, revision, etc).