diff --git a/setup/mscs/msc2946/msc2946.go b/setup/mscs/msc2946/msc2946.go
index 4da9edf96..6d169573d 100644
--- a/setup/mscs/msc2946/msc2946.go
+++ b/setup/mscs/msc2946/msc2946.go
@@ -171,7 +171,7 @@ func (w *walker) walk() (*SpacesResponse, *util.JSONResponse) {
 		roomID := unvisited[0]
 		unvisited = unvisited[1:]
 		// If this room has already been processed, skip. NB: do not remember this between calls
-		if processed[roomID] {
+		if processed[roomID] || roomID == "" {
 			continue
 		}
 		// Mark this room as processed.
@@ -219,6 +219,7 @@ func (w *walker) walk() (*SpacesResponse, *util.JSONResponse) {
 						ev, gomatrixserverlib.FormatAll,
 					))
 					uniqueRooms[ev.RoomID()] = true
+					uniqueRooms[SpaceTarget(ev)] = true
 					w.markSent(ev.EventID())
 				}
 			}
@@ -227,10 +228,10 @@ func (w *walker) walk() (*SpacesResponse, *util.JSONResponse) {
 			// are exceeded, stop adding events. If the event has already been added, do not add it again.
 			numAdded := 0
 			for _, ev := range refs.events() {
-				if len(res.Events) >= w.req.Limit {
+				if w.req.Limit > 0 && len(res.Events) >= w.req.Limit {
 					break
 				}
-				if numAdded >= w.req.MaxRoomsPerSpace {
+				if w.req.MaxRoomsPerSpace > 0 && numAdded >= w.req.MaxRoomsPerSpace {
 					break
 				}
 				if w.alreadySent(ev.EventID()) {
@@ -240,6 +241,7 @@ func (w *walker) walk() (*SpacesResponse, *util.JSONResponse) {
 					ev, gomatrixserverlib.FormatAll,
 				))
 				uniqueRooms[ev.RoomID()] = true
+				uniqueRooms[SpaceTarget(ev)] = true
 				w.markSent(ev.EventID())
 				// we don't distinguish between child state events and parent state events for the purposes of
 				// max_rooms_per_space, maybe we should?
@@ -331,9 +333,9 @@ func (el eventLookup) get(roomID, evType, stateKey string) *gomatrixserverlib.He
 func (el eventLookup) set(ev *gomatrixserverlib.HeaderedEvent) {
 	evs := el[ev.Type()]
 	if evs == nil {
-		evs = make([]*gomatrixserverlib.HeaderedEvent, 1)
+		evs = make([]*gomatrixserverlib.HeaderedEvent, 0)
 	}
-	evs[0] = ev
+	evs = append(evs, ev)
 	el[ev.Type()] = evs
 }
 
diff --git a/setup/mscs/msc2946/msc2946_test.go b/setup/mscs/msc2946/msc2946_test.go
index 587dc5b42..1eaf7cf65 100644
--- a/setup/mscs/msc2946/msc2946_test.go
+++ b/setup/mscs/msc2946/msc2946_test.go
@@ -57,8 +57,10 @@ var (
 //             |_________
 //             |    |   |
 //             R3   R4  S2
-//                      |
+//                      |  <-- this link is just a parent, not a child
 //                      R5
+//
+// TODO: Alice is not joined to R4, but R4 is "world_readable".
 func TestMSC2946(t *testing.T) {
 	alice := "@alice:localhost"
 	// give access tokens to all three users
@@ -77,6 +79,7 @@ func TestMSC2946(t *testing.T) {
 	room2 := "!room2:localhost"
 	room3 := "!room3:localhost"
 	room4 := "!room4:localhost"
+	empty := ""
 	room5 := "!room5:localhost"
 	allRooms := []string{
 		rootSpace, subSpaceS1, subSpaceS2,
@@ -142,16 +145,26 @@ func TestMSC2946(t *testing.T) {
 			"present": true,
 		},
 	})
+	// This is a parent link only
 	s2ToR5 := mustCreateEvent(t, fledglingEvent{
-		RoomID:   subSpaceS2,
+		RoomID:   room5,
 		Sender:   alice,
-		Type:     msc2946.ConstSpaceChildEventType,
-		StateKey: &room5,
+		Type:     msc2946.ConstSpaceParentEventType,
+		StateKey: &empty,
 		Content: map[string]interface{}{
+			"room_id": subSpaceS2,
 			"via":     []string{"localhost"},
 			"present": true,
 		},
 	})
+	roomNameTuple := gomatrixserverlib.StateKeyTuple{
+		EventType: "m.room.name",
+		StateKey:  "",
+	}
+	hisVisTuple := gomatrixserverlib.StateKeyTuple{
+		EventType: "m.room.history_visibility",
+		StateKey:  "",
+	}
 	nopRsAPI := &testRoomserverAPI{
 		userToJoinedRooms: map[string][]string{
 			alice: allRooms,
@@ -165,6 +178,35 @@ func TestMSC2946(t *testing.T) {
 			s1ToS2.EventID():   s1ToS2,
 			s2ToR5.EventID():   s2ToR5,
 		},
+		pubRoomState: map[string]map[gomatrixserverlib.StateKeyTuple]string{
+			rootSpace: {
+				roomNameTuple: "Root",
+				hisVisTuple:   "shared",
+			},
+			subSpaceS1: {
+				roomNameTuple: "Sub-Space 1",
+				hisVisTuple:   "joined",
+			},
+			subSpaceS2: {
+				roomNameTuple: "Sub-Space 2",
+				hisVisTuple:   "shared",
+			},
+			room1: {
+				hisVisTuple: "joined",
+			},
+			room2: {
+				hisVisTuple: "joined",
+			},
+			room3: {
+				hisVisTuple: "joined",
+			},
+			room4: {
+				hisVisTuple: "world_readable",
+			},
+			room5: {
+				hisVisTuple: "joined",
+			},
+		},
 	}
 	router := injectEvents(t, nopUserAPI, nopRsAPI, []*gomatrixserverlib.HeaderedEvent{
 		rootToR1, rootToR2, rootToS1,
@@ -183,6 +225,16 @@ func TestMSC2946(t *testing.T) {
 			t.Errorf("got %d rooms, want 0", len(res.Rooms))
 		}
 	})
+	t.Run("returns the entire graph", func(t *testing.T) {
+		res := postSpaces(t, 200, "alice", rootSpace, newReq(t, map[string]interface{}{}))
+		if len(res.Events) != 7 {
+			t.Errorf("got %d events, want 7", len(res.Events))
+		}
+		if len(res.Rooms) != len(allRooms) {
+			t.Errorf("got %d rooms, want %d", len(res.Rooms), len(allRooms))
+		}
+
+	})
 }
 
 func newReq(t *testing.T, jsonBody map[string]interface{}) *msc2946.SpacesRequest {
@@ -245,6 +297,7 @@ func postSpaces(t *testing.T, expectCode int, accessToken, roomID string, req *m
 		if err != nil {
 			t.Fatalf("response 200 OK but failed to read response body: %s", err)
 		}
+		t.Logf("Body: %s", string(body))
 		if err := json.Unmarshal(body, &result); err != nil {
 			t.Fatalf("response 200 OK but failed to deserialise JSON : %s\nbody: %s", err, string(body))
 		}
@@ -365,13 +418,37 @@ type testRoomserverAPI struct {
 	roomserver.RoomserverInternalAPITrace
 	userToJoinedRooms map[string][]string
 	events            map[string]*gomatrixserverlib.HeaderedEvent
+	pubRoomState      map[string]map[gomatrixserverlib.StateKeyTuple]string
 }
 
-func (r *testRoomserverAPI) QueryEventsByID(ctx context.Context, req *roomserver.QueryEventsByIDRequest, res *roomserver.QueryEventsByIDResponse) error {
-	for _, eventID := range req.EventIDs {
-		ev := r.events[eventID]
-		if ev != nil {
-			res.Events = append(res.Events, ev)
+func (r *testRoomserverAPI) QueryBulkStateContent(ctx context.Context, req *roomserver.QueryBulkStateContentRequest, res *roomserver.QueryBulkStateContentResponse) error {
+	res.Rooms = make(map[string]map[gomatrixserverlib.StateKeyTuple]string)
+	for _, roomID := range req.RoomIDs {
+		pubRoomData, ok := r.pubRoomState[roomID]
+		if ok {
+			res.Rooms[roomID] = pubRoomData
+		}
+	}
+	return nil
+}
+
+func (r *testRoomserverAPI) QueryCurrentState(ctx context.Context, req *roomserver.QueryCurrentStateRequest, res *roomserver.QueryCurrentStateResponse) error {
+	res.StateEvents = make(map[gomatrixserverlib.StateKeyTuple]*gomatrixserverlib.HeaderedEvent)
+	for _, he := range r.events {
+		if he.RoomID() != req.RoomID {
+			continue
+		}
+		if he.StateKey() == nil {
+			continue
+		}
+		tuple := gomatrixserverlib.StateKeyTuple{
+			EventType: he.Type(),
+			StateKey:  *he.StateKey(),
+		}
+		for _, t := range req.StateTuples {
+			if t == tuple {
+				res.StateEvents[t] = he
+			}
 		}
 	}
 	return nil
diff --git a/setup/mscs/msc2946/storage.go b/setup/mscs/msc2946/storage.go
index 69096e64b..a1b59c817 100644
--- a/setup/mscs/msc2946/storage.go
+++ b/setup/mscs/msc2946/storage.go
@@ -18,31 +18,170 @@ import (
 	"context"
 	"database/sql"
 
+	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/tidwall/gjson"
+)
+
+var (
+	relTypes = map[string]int{
+		ConstSpaceChildEventType:  1,
+		ConstSpaceParentEventType: 2,
+	}
+	relTypesEnum = map[int]string{
+		1: ConstSpaceChildEventType,
+		2: ConstSpaceParentEventType,
+	}
 )
 
 type Database interface {
+	// StoreReference persists a child or parent space mapping.
 	StoreReference(ctx context.Context, he *gomatrixserverlib.HeaderedEvent) error
+	// References returns all events which have the given roomID as a parent or child space.
 	References(ctx context.Context, roomID string) ([]*gomatrixserverlib.HeaderedEvent, error)
 }
 
 type DB struct {
-	db             *sql.DB
-	writer         sqlutil.Writer
-	insertEdgeStmt *sql.Stmt
+	db              *sql.DB
+	writer          sqlutil.Writer
+	insertEdgeStmt  *sql.Stmt
+	selectEdgesStmt *sql.Stmt
 }
 
 // NewDatabase loads the database for msc2836
 func NewDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
-	return &DB{}, nil
+	if dbOpts.ConnectionString.IsPostgres() {
+		return newPostgresDatabase(dbOpts)
+	}
+	return newSQLiteDatabase(dbOpts)
+}
+
+func newPostgresDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewDummyWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2946_edges (
+		room_version TEXT NOT NULL,
+		-- the room ID of the event, the source of the arrow
+		source_room_id TEXT NOT NULL,
+		-- the target room ID, the arrow destination
+		dest_room_id TEXT NOT NULL,
+		-- the kind of relation, either child or parent (1,2)
+		rel_type SMALLINT NOT NULL,
+		event_json TEXT NOT NULL,
+		CONSTRAINT msc2946_edges_uniq UNIQUE (source_room_id, dest_room_id, rel_type)
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2946_edges(room_version, source_room_id, dest_room_id, rel_type, event_json)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectEdgesStmt, err = d.db.Prepare(`
+		SELECT room_version, event_json FROM msc2946_edges
+		WHERE source_room_id = $1 OR dest_room_id = $2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, err
+}
+
+func newSQLiteDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2946_edges (
+		room_version TEXT NOT NULL,
+		-- the room ID of the event, the source of the arrow
+		source_room_id TEXT NOT NULL,
+		-- the target room ID, the arrow destination
+		dest_room_id TEXT NOT NULL,
+		-- the kind of relation, either child or parent (1,2)
+		rel_type SMALLINT NOT NULL,
+		event_json TEXT NOT NULL,
+		UNIQUE (source_room_id, dest_room_id, rel_type)
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2946_edges(room_version, source_room_id, dest_room_id, rel_type, event_json)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectEdgesStmt, err = d.db.Prepare(`
+		SELECT room_version, event_json FROM msc2946_edges
+		WHERE source_room_id = $1 OR dest_room_id = $2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, err
 }
 
 func (d *DB) StoreReference(ctx context.Context, he *gomatrixserverlib.HeaderedEvent) error {
-	return nil
+	target := SpaceTarget(he)
+	if target == "" {
+		return nil // malformed event
+	}
+	relType := relTypes[he.Type()]
+	_, err := d.insertEdgeStmt.ExecContext(ctx, he.RoomVersion, he.RoomID(), target, relType, he.JSON())
+	return err
 }
 
 func (d *DB) References(ctx context.Context, roomID string) ([]*gomatrixserverlib.HeaderedEvent, error) {
-	return nil, nil
+	rows, err := d.selectEdgesStmt.QueryContext(ctx, roomID, roomID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "failed to close References")
+	refs := make([]*gomatrixserverlib.HeaderedEvent, 0)
+	for rows.Next() {
+		var roomVer string
+		var jsonBytes []byte
+		if err := rows.Scan(&roomVer, &jsonBytes); err != nil {
+			return nil, err
+		}
+		ev, err := gomatrixserverlib.NewEventFromTrustedJSON(jsonBytes, false, gomatrixserverlib.RoomVersion(roomVer))
+		if err != nil {
+			return nil, err
+		}
+		he := ev.Headered(gomatrixserverlib.RoomVersion(roomVer))
+		refs = append(refs, he)
+	}
+	return refs, nil
+}
+
+// SpaceTarget returns the destination room ID for the space event. This is either a child or a parent
+// depending on the event type.
+func SpaceTarget(he *gomatrixserverlib.HeaderedEvent) string {
+	if he.StateKey() == nil {
+		return "" // no-op
+	}
+	switch he.Type() {
+	case ConstSpaceParentEventType:
+		return gjson.GetBytes(he.Content(), "room_id").Str
+	case ConstSpaceChildEventType:
+		return *he.StateKey()
+	}
+	return ""
 }