A bunch of comments from review

state/event_table.go

@@ -128,7 +128,8 @@ func NewEventTable(db *sqlx.DB) *EventTable {
 		membership TEXT,
 		is_state BOOLEAN NOT NULL, -- is this event part of the v2 state response?
 		event BYTEA NOT NULL,
-		-- True iff the previous timeline event is not known to the proxy.
+		-- True iff this event was seen at the start of the timeline in a limited sync
+		-- (i.e. the preceding timeline event was not known to the proxy).
 		missing_previous BOOLEAN NOT NULL DEFAULT FALSE
 	);
 

state/event_table_test.go

@@ -1169,7 +1169,9 @@ func TestEventTable_SelectLatestEventsBetween_MissingPrevious(t *testing.T) {
 		Desc            string
 		FromIDExclusive string
 		ToIDInclusive   string
-		ExpectIDs       []string
+		// NB: ExpectIDs is ordered from newest to oldest. Surprising, but this is what
+		// SelectLatestEventsBetween returns.
+		ExpectIDs []string
 	}{
 		{
 			Desc:            "has no gaps - should omit nothing",