diff --git a/roomserver/storage/postgres/events_table.go b/roomserver/storage/postgres/events_table.go
index 662dbbf00..8012174a0 100644
--- a/roomserver/storage/postgres/events_table.go
+++ b/roomserver/storage/postgres/events_table.go
@@ -463,9 +463,22 @@ func (s *eventStatements) BulkSelectEventID(ctx context.Context, txn *sql.Tx, ev
 	return results, nil
 }
 
+// BulkSelectEventNIDs returns a map from string event ID to numeric event ID.
+// If an event ID is not in the database then it is omitted from the map.
+func (s *eventStatements) BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error) {
+	return s.bulkSelectEventNID(ctx, txn, eventIDs, false)
+}
+
+// BulkSelectEventNIDs returns a map from string event ID to numeric event ID
+// only for events that haven't already been sent to the roomserver output.
+// If an event ID is not in the database then it is omitted from the map.
+func (s *eventStatements) BulkSelectUnsentEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error) {
+	return s.bulkSelectEventNID(ctx, txn, eventIDs, true)
+}
+
 // bulkSelectEventNIDs returns a map from string event ID to numeric event ID.
 // If an event ID is not in the database then it is omitted from the map.
-func (s *eventStatements) BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) (map[string]types.EventNID, error) {
+func (s *eventStatements) bulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) (map[string]types.EventNID, error) {
 	var stmt *sql.Stmt
 	if onlyUnsent {
 		stmt = sqlutil.TxStmt(txn, s.bulkSelectUnsentEventNIDStmt)
diff --git a/roomserver/storage/shared/room_updater.go b/roomserver/storage/shared/room_updater.go
index b148f8acd..810a18ef2 100644
--- a/roomserver/storage/shared/room_updater.go
+++ b/roomserver/storage/shared/room_updater.go
@@ -215,13 +215,13 @@ func (u *RoomUpdater) EventIDs(
 func (u *RoomUpdater) EventNIDs(
 	ctx context.Context, eventIDs []string,
 ) (map[string]types.EventNID, error) {
-	return u.d.eventNIDs(ctx, u.txn, eventIDs, false)
+	return u.d.eventNIDs(ctx, u.txn, eventIDs, NoFilter)
 }
 
 func (u *RoomUpdater) UnsentEventNIDs(
 	ctx context.Context, eventIDs []string,
 ) (map[string]types.EventNID, error) {
-	return u.d.eventNIDs(ctx, u.txn, eventIDs, true)
+	return u.d.eventNIDs(ctx, u.txn, eventIDs, FilterUnsentOnly)
 }
 
 func (u *RoomUpdater) StateAtEventIDs(
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index 256aa47f0..9f3b8b1da 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -238,13 +238,27 @@ func (d *Database) addState(
 func (d *Database) EventNIDs(
 	ctx context.Context, eventIDs []string,
 ) (map[string]types.EventNID, error) {
-	return d.eventNIDs(ctx, nil, eventIDs, false)
+	return d.eventNIDs(ctx, nil, eventIDs, NoFilter)
 }
 
+type UnsentFilter bool
+
+const (
+	NoFilter         UnsentFilter = false
+	FilterUnsentOnly UnsentFilter = true
+)
+
 func (d *Database) eventNIDs(
-	ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool,
+	ctx context.Context, txn *sql.Tx, eventIDs []string, filter UnsentFilter,
 ) (map[string]types.EventNID, error) {
-	return d.EventsTable.BulkSelectEventNID(ctx, txn, eventIDs, onlyUnsent)
+	switch filter {
+	case FilterUnsentOnly:
+		return d.EventsTable.BulkSelectUnsentEventNID(ctx, txn, eventIDs)
+	case NoFilter:
+		return d.EventsTable.BulkSelectEventNID(ctx, txn, eventIDs)
+	default:
+		panic("impossible case")
+	}
 }
 
 func (d *Database) SetState(
@@ -281,11 +295,11 @@ func (d *Database) EventIDs(
 }
 
 func (d *Database) EventsFromIDs(ctx context.Context, eventIDs []string) ([]types.Event, error) {
-	return d.eventsFromIDs(ctx, nil, eventIDs, false)
+	return d.eventsFromIDs(ctx, nil, eventIDs, NoFilter)
 }
 
-func (d *Database) eventsFromIDs(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) ([]types.Event, error) {
-	nidMap, err := d.eventNIDs(ctx, txn, eventIDs, onlyUnsent)
+func (d *Database) eventsFromIDs(ctx context.Context, txn *sql.Tx, eventIDs []string, filter UnsentFilter) ([]types.Event, error) {
+	nidMap, err := d.eventNIDs(ctx, txn, eventIDs, filter)
 	if err != nil {
 		return nil, err
 	}
diff --git a/roomserver/storage/sqlite3/events_table.go b/roomserver/storage/sqlite3/events_table.go
index e49b23739..969a10ce5 100644
--- a/roomserver/storage/sqlite3/events_table.go
+++ b/roomserver/storage/sqlite3/events_table.go
@@ -499,9 +499,22 @@ func (s *eventStatements) BulkSelectEventID(ctx context.Context, txn *sql.Tx, ev
 	return results, nil
 }
 
+// BulkSelectEventNIDs returns a map from string event ID to numeric event ID.
+// If an event ID is not in the database then it is omitted from the map.
+func (s *eventStatements) BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error) {
+	return s.bulkSelectEventNID(ctx, txn, eventIDs, false)
+}
+
+// BulkSelectEventNIDs returns a map from string event ID to numeric event ID
+// only for events that haven't already been sent to the roomserver output.
+// If an event ID is not in the database then it is omitted from the map.
+func (s *eventStatements) BulkSelectUnsentEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error) {
+	return s.bulkSelectEventNID(ctx, txn, eventIDs, true)
+}
+
 // bulkSelectEventNIDs returns a map from string event ID to numeric event ID.
 // If an event ID is not in the database then it is omitted from the map.
-func (s *eventStatements) BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) (map[string]types.EventNID, error) {
+func (s *eventStatements) bulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) (map[string]types.EventNID, error) {
 	///////////////
 	iEventIDs := make([]interface{}, len(eventIDs))
 	for k, v := range eventIDs {
diff --git a/roomserver/storage/tables/interface.go b/roomserver/storage/tables/interface.go
index 24fef2036..e3fed700b 100644
--- a/roomserver/storage/tables/interface.go
+++ b/roomserver/storage/tables/interface.go
@@ -58,7 +58,8 @@ type Events interface {
 	BulkSelectEventID(ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID) (map[types.EventNID]string, error)
 	// BulkSelectEventNIDs returns a map from string event ID to numeric event ID.
 	// If an event ID is not in the database then it is omitted from the map.
-	BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string, onlyUnsent bool) (map[string]types.EventNID, error)
+	BulkSelectEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error)
+	BulkSelectUnsentEventNID(ctx context.Context, txn *sql.Tx, eventIDs []string) (map[string]types.EventNID, error)
 	SelectMaxEventDepth(ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID) (int64, error)
 	SelectRoomNIDsForEventNIDs(ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID) (roomNIDs map[types.EventNID]types.RoomNID, err error)
 }