diff --git a/src/github.com/matrix-org/dendrite/federationsender/storage/joined_hosts_table.go b/src/github.com/matrix-org/dendrite/federationsender/storage/joined_hosts_table.go
index dcbc62a88..1b5c65ddf 100644
--- a/src/github.com/matrix-org/dendrite/federationsender/storage/joined_hosts_table.go
+++ b/src/github.com/matrix-org/dendrite/federationsender/storage/joined_hosts_table.go
@@ -25,10 +25,11 @@ import (
 const joinedHostsSchema = `
 -- The joined_hosts table stores a list of m.room.member event ids in the
 -- current state for each room where the membership is "join".
+-- There will be an entry for every user that is joined to the room.
 CREATE TABLE IF NOT EXISTS joined_hosts (
     -- The string ID of the room.
     room_id TEXT NOT NULL,
-    -- The event ID of the m.room.member
+    -- The event ID of the m.room.member join event.
     event_id TEXT NOT NULL,
     -- The domain part of the user ID the m.room.member event is for.
     server_name TEXT NOT NULL