diff --git a/roomserver/storage/postgres/deltas/20210622210900_add_displayname_column.go b/roomserver/storage/postgres/deltas/20210622210900_add_displayname_column.go
new file mode 100644
index 000000000..bba5b325b
--- /dev/null
+++ b/roomserver/storage/postgres/deltas/20210622210900_add_displayname_column.go
@@ -0,0 +1,43 @@
+
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package deltas
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+func LoadAddDisplaynameColumn(m *sqlutil.Migrations) {
+	m.AddMigration(UpAddForgottenColumn, DownAddForgottenColumn)
+}
+
+func UpAddDisplaynameColumn(tx *sql.Tx) error {
+	_, err := tx.Exec(`ALTER TABLE roomserver_membership ADD COLUMN IF NOT EXISTS displayname TEXT DEFAULT "";`)
+	if err != nil {
+		return fmt.Errorf("failed to execute upgrade: %w", err)
+	}
+	return nil
+}
+
+func DownAddDisplaynameColumn(tx *sql.Tx) error {
+	_, err := tx.Exec(`ALTER TABLE roomserver_membership DROP COLUMN IF EXISTS displayname;`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	return nil
+}
diff --git a/roomserver/storage/postgres/membership_table.go b/roomserver/storage/postgres/membership_table.go
index c7d48d6e9..3cfc09fd0 100644
--- a/roomserver/storage/postgres/membership_table.go
+++ b/roomserver/storage/postgres/membership_table.go
@@ -61,6 +61,7 @@ CREATE TABLE IF NOT EXISTS roomserver_membership (
 	-- room joins.
 	target_local BOOLEAN NOT NULL DEFAULT false,
 	forgotten BOOLEAN NOT NULL DEFAULT FALSE,
+	displayname TEXT,
 	UNIQUE (room_nid, target_nid)
 );
 `
@@ -104,7 +105,7 @@ const selectMembershipForUpdateSQL = "" +
 	" WHERE room_nid = $1 AND target_nid = $2 FOR UPDATE"
 
 const updateMembershipSQL = "" +
-	"UPDATE roomserver_membership SET sender_nid = $3, membership_nid = $4, event_nid = $5, forgotten = $6" +
+	"UPDATE roomserver_membership SET sender_nid = $3, membership_nid = $4, event_nid = $5, forgotten = $6, displayname = $7" +
 	" WHERE room_nid = $1 AND target_nid = $2"
 
 const updateMembershipForgetRoom = "" +
@@ -118,11 +119,16 @@ const selectRoomsWithMembershipSQL = "" +
 // joined to. Since this information is used to populate the user directory, we will
 // only return users that the user would ordinarily be able to see anyway.
 var selectKnownUsersSQL = "" +
-	"SELECT DISTINCT event_state_key FROM roomserver_membership INNER JOIN roomserver_event_state_keys ON " +
-	"roomserver_membership.target_nid = roomserver_event_state_keys.event_state_key_nid" +
-	" WHERE room_nid = ANY(" +
-	"  SELECT DISTINCT room_nid FROM roomserver_membership WHERE target_nid=$1 AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) +
-	") AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) + " AND event_state_key LIKE $2 LIMIT $3"
+	"SELECT DISTINCT event_state_key, displayname FROM roomserver_membership INNER JOIN roomserver_event_state_keys ON " +
+	"roomserver_membership.target_nid = roomserver_event_state_keys.event_state_key_nid " +
+	"WHERE room_nid IN (" +
+	"   SELECT DISTINCT room_nid FROM roomserver_membership WHERE target_nid = $1 AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) +
+	" UNION " +
+	"   SELECT DISTINCT room_nid from roomserver_rooms INNER JOIN roomserver_published ON  " +
+	"   roomserver_rooms.room_id = roomserver_published.room_id WHERE published = true " +
+	") AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) + " AND ( " +
+	" event_state_key LIKE $2 OR displayname LIKE $2" +
+	") LIMIT $3"
 
 type membershipStatements struct {
 	insertMembershipStmt                            *sql.Stmt
@@ -251,7 +257,7 @@ func (s *membershipStatements) UpdateMembership(
 	eventNID types.EventNID, forgotten bool, displayname *string,
 ) error {
 	_, err := sqlutil.TxStmt(txn, s.updateMembershipStmt).ExecContext(
-		ctx, roomNID, targetUserNID, senderUserNID, membership, eventNID, forgotten,
+		ctx, roomNID, targetUserNID, senderUserNID, membership, eventNID, forgotten, displayname,
 	)
 	return err
 }
@@ -306,7 +312,8 @@ func (s *membershipStatements) SelectKnownUsers(ctx context.Context, userID type
 	defer internal.CloseAndLogIfError(ctx, rows, "SelectKnownUsers: rows.close() failed")
 	for rows.Next() {
 		var userID string
-		if err := rows.Scan(&userID); err != nil {
+		var displayname string
+		if err := rows.Scan(&userID, &displayname); err != nil {
 			return nil, err
 		}
 		result = append(result, userID)
diff --git a/roomserver/storage/postgres/storage.go b/roomserver/storage/postgres/storage.go
index 863a15939..2c756bd86 100644
--- a/roomserver/storage/postgres/storage.go
+++ b/roomserver/storage/postgres/storage.go
@@ -53,6 +53,7 @@ func Open(dbProperties *config.DatabaseOptions, cache caching.RoomServerCaches)
 	m := sqlutil.NewMigrations()
 	deltas.LoadAddForgottenColumn(m)
 	deltas.LoadStateBlocksRefactor(m)
+	deltas.LoadAddDisplaynameColumn(m)
 	if err := m.RunDeltas(db, dbProperties); err != nil {
 		return nil, err
 	}
@@ -60,7 +61,7 @@ func Open(dbProperties *config.DatabaseOptions, cache caching.RoomServerCaches)
 	// Then prepare the statements. Now that the migrations have run, any columns referred
 	// to in the database code should now exist.
 	if err := d.prepare(db, cache); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("Error preparing statements: %v", err)
 	}
 
 	return &d, nil
diff --git a/roomserver/storage/sqlite3/deltas/20210622210900_add_displayname_column.go b/roomserver/storage/sqlite3/deltas/20210622210900_add_displayname_column.go
index cd7863560..81320a411 100644
--- a/roomserver/storage/sqlite3/deltas/20210622210900_add_displayname_column.go
+++ b/roomserver/storage/sqlite3/deltas/20210622210900_add_displayname_column.go
@@ -26,26 +26,7 @@ func LoadAddDisplaynameColumn(m *sqlutil.Migrations) {
 }
 
 func UpAddDisplaynameColumn(tx *sql.Tx) error {
-	_, err := tx.Exec(`	ALTER TABLE roomserver_membership RENAME TO roomserver_membership_tmp;
-CREATE TABLE IF NOT EXISTS roomserver_membership (
-	room_nid INTEGER NOT NULL,
-	target_nid INTEGER NOT NULL,
-	sender_nid INTEGER NOT NULL DEFAULT 0,
-	membership_nid INTEGER NOT NULL DEFAULT 1,
-	event_nid INTEGER NOT NULL DEFAULT 0,
-	target_local BOOLEAN NOT NULL DEFAULT false,
-	forgotten BOOLEAN NOT NULL DEFAULT false,
-	displayname TEXT,
-	UNIQUE (room_nid, target_nid)
-);
-INSERT
-    INTO roomserver_membership (
-      room_nid, target_nid, sender_nid, membership_nid, event_nid, target_local, forgotten
-    ) SELECT
-        room_nid, target_nid, sender_nid, membership_nid, event_nid, target_local, forgotten
-    FROM roomserver_membership_tmp
-;
-DROP TABLE roomserver_membership_tmp;`)
+	_, err := tx.Exec(`ALTER TABLE roomserver_membership ADD COLUMN IF NOT EXISTS displayname TEXT DEFAULT "";`)
 	if err != nil {
 		return fmt.Errorf("failed to execute upgrade: %w", err)
 	}
@@ -53,25 +34,7 @@ DROP TABLE roomserver_membership_tmp;`)
 }
 
 func DownAddDisplaynameColumn(tx *sql.Tx) error {
-	_, err := tx.Exec(`	ALTER TABLE roomserver_membership RENAME TO roomserver_membership_tmp;
-CREATE TABLE IF NOT EXISTS roomserver_membership (
-	room_nid INTEGER NOT NULL,
-	target_nid INTEGER NOT NULL,
-	sender_nid INTEGER NOT NULL DEFAULT 0,
-	membership_nid INTEGER NOT NULL DEFAULT 1,
-	event_nid INTEGER NOT NULL DEFAULT 0,
-	target_local BOOLEAN NOT NULL DEFAULT false,
-	forgotten BOOLEAN NOT NULL DEFAULT false,
-	UNIQUE (room_nid, target_nid)
-);
-INSERT
-    INTO roomserver_membership (
-      room_nid, target_nid, sender_nid, membership_nid, event_nid, target_local, forgotten
-    ) SELECT
-        room_nid, target_nid, sender_nid, membership_nid, event_nid, target_local, forgotten
-    FROM roomserver_membership_tmp
-;
-DROP TABLE roomserver_membership_tmp;`)
+	_, err := tx.Exec(`ALTER TABLE roomserver_membership DROP COLUMN IF EXISTS displayname;`)
 	if err != nil {
 		return fmt.Errorf("failed to execute downgrade: %w", err)
 	}