diff --git a/roomserver/internal/helpers/auth.go b/roomserver/internal/helpers/auth.go
index 1f4215e7..e69f4c93 100644
--- a/roomserver/internal/helpers/auth.go
+++ b/roomserver/internal/helpers/auth.go
@@ -56,7 +56,7 @@ func CheckForSoftFail(
 
 		// Then get the state entries for the current state snapshot.
 		// We'll use this to check if the event is allowed right now.
-		roomState := state.NewStateResolution(db, *roomInfo)
+		roomState := state.NewStateResolution(db, *roomInfo, nil)
 		authStateEntries, err = roomState.LoadStateAtSnapshot(ctx, roomInfo.StateSnapshotNID)
 		if err != nil {
 			return true, fmt.Errorf("roomState.LoadStateAtSnapshot: %w", err)
diff --git a/roomserver/internal/helpers/helpers.go b/roomserver/internal/helpers/helpers.go
index a829bffc..680628fb 100644
--- a/roomserver/internal/helpers/helpers.go
+++ b/roomserver/internal/helpers/helpers.go
@@ -172,7 +172,7 @@ func GetMembershipsAtState(
 }
 
 func StateBeforeEvent(ctx context.Context, db storage.Database, info types.RoomInfo, eventNID types.EventNID) ([]types.StateEntry, error) {
-	roomState := state.NewStateResolution(db, info)
+	roomState := state.NewStateResolution(db, info, nil)
 	// Lookup the event NID
 	eIDs, err := db.EventIDs(ctx, []types.EventNID{eventNID})
 	if err != nil {
@@ -217,7 +217,7 @@ func LoadStateEvents(
 func CheckServerAllowedToSeeEvent(
 	ctx context.Context, db storage.Database, info types.RoomInfo, eventID string, serverName gomatrixserverlib.ServerName, isServerInRoom bool,
 ) (bool, error) {
-	roomState := state.NewStateResolution(db, info)
+	roomState := state.NewStateResolution(db, info, nil)
 	stateEntries, err := roomState.LoadStateAtEvent(ctx, eventID)
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
@@ -379,7 +379,7 @@ func QueryLatestEventsAndState(
 		return nil
 	}
 
-	roomState := state.NewStateResolution(db, *roomInfo)
+	roomState := state.NewStateResolution(db, *roomInfo, nil)
 	response.RoomExists = true
 	response.RoomVersion = roomInfo.RoomVersion
 
diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 2a558c48..46727c21 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -249,7 +249,7 @@ func (r *Inputer) calculateAndSetState(
 	isRejected bool,
 ) error {
 	var err error
-	roomState := state.NewStateResolution(r.DB, roomInfo)
+	roomState := state.NewStateResolution(r.DB, roomInfo, nil)
 
 	if input.HasState && !isRejected {
 		// Check here if we think we're in the room already.
@@ -271,7 +271,7 @@ func (r *Inputer) calculateAndSetState(
 		}
 		entries = types.DeduplicateStateEntries(entries)
 
-		if stateAtEvent.BeforeStateSnapshotNID, err = r.DB.AddState(ctx, roomInfo.RoomNID, nil, entries); err != nil {
+		if stateAtEvent.BeforeStateSnapshotNID, err = r.DB.AddState(ctx, nil, roomInfo.RoomNID, nil, entries); err != nil {
 			return fmt.Errorf("r.DB.AddState: %w", err)
 		}
 	} else {
diff --git a/roomserver/internal/input/input_latest_events.go b/roomserver/internal/input/input_latest_events.go
index c9264a27..f9b79670 100644
--- a/roomserver/internal/input/input_latest_events.go
+++ b/roomserver/internal/input/input_latest_events.go
@@ -199,7 +199,7 @@ func (u *latestEventsUpdater) doUpdateLatestEvents() error {
 
 func (u *latestEventsUpdater) latestState() error {
 	var err error
-	roomState := state.NewStateResolution(u.api.DB, *u.roomInfo)
+	roomState := state.NewStateResolution(u.api.DB, *u.roomInfo, u.updater.Txn)
 
 	// Work out if the state at the extremities has actually changed
 	// or not. If they haven't then we won't bother doing all of the
diff --git a/roomserver/internal/perform/perform_backfill.go b/roomserver/internal/perform/perform_backfill.go
index d9d720f2..6c33f3c8 100644
--- a/roomserver/internal/perform/perform_backfill.go
+++ b/roomserver/internal/perform/perform_backfill.go
@@ -146,7 +146,7 @@ func (r *Backfiller) backfillViaFederation(ctx context.Context, req *api.Perform
 		}
 
 		var beforeStateSnapshotNID types.StateSnapshotNID
-		if beforeStateSnapshotNID, err = r.DB.AddState(ctx, roomNID, nil, entries); err != nil {
+		if beforeStateSnapshotNID, err = r.DB.AddState(ctx, nil, roomNID, nil, entries); err != nil {
 			logrus.WithError(err).WithField("event_id", ev.EventID()).Error("backfillViaFederation: failed to persist state entries to get snapshot nid")
 			return err
 		}
diff --git a/roomserver/internal/perform/perform_inbound_peek.go b/roomserver/internal/perform/perform_inbound_peek.go
index eb3c9727..7fbc101f 100644
--- a/roomserver/internal/perform/perform_inbound_peek.go
+++ b/roomserver/internal/perform/perform_inbound_peek.go
@@ -79,7 +79,7 @@ func (r *InboundPeeker) PerformInboundPeek(
 	response.LatestEvent = sortedLatestEvents[0].Headered(info.RoomVersion)
 
 	// XXX: do we actually need to do a state resolution here?
-	roomState := state.NewStateResolution(r.DB, *info)
+	roomState := state.NewStateResolution(r.DB, *info, nil)
 
 	var stateEntries []types.StateEntry
 	stateEntries, err = roomState.LoadStateAtSnapshot(
diff --git a/roomserver/internal/perform/perform_invite.go b/roomserver/internal/perform/perform_invite.go
index fa65ce9b..7293a1e7 100644
--- a/roomserver/internal/perform/perform_invite.go
+++ b/roomserver/internal/perform/perform_invite.go
@@ -231,7 +231,7 @@ func buildInviteStrippedState(
 			StateKey:  "",
 		})
 	}
-	roomState := state.NewStateResolution(db, *info)
+	roomState := state.NewStateResolution(db, *info, nil)
 	stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples(
 		ctx, info.StateSnapshotNID, stateWanted,
 	)
diff --git a/roomserver/internal/query/query.go b/roomserver/internal/query/query.go
index f69f67f7..60581133 100644
--- a/roomserver/internal/query/query.go
+++ b/roomserver/internal/query/query.go
@@ -62,7 +62,7 @@ func (r *Queryer) QueryStateAfterEvents(
 		return nil
 	}
 
-	roomState := state.NewStateResolution(r.DB, *info)
+	roomState := state.NewStateResolution(r.DB, *info, nil)
 	response.RoomExists = true
 	response.RoomVersion = info.RoomVersion
 
@@ -507,7 +507,7 @@ func (r *Queryer) QueryStateAndAuthChain(
 }
 
 func (r *Queryer) loadStateAtEventIDs(ctx context.Context, roomInfo types.RoomInfo, eventIDs []string) ([]*gomatrixserverlib.Event, error) {
-	roomState := state.NewStateResolution(r.DB, roomInfo)
+	roomState := state.NewStateResolution(r.DB, roomInfo, nil)
 	prevStates, err := r.DB.StateAtEventIDs(ctx, eventIDs)
 	if err != nil {
 		switch err.(type) {
diff --git a/roomserver/state/state.go b/roomserver/state/state.go
index 0d9511ac..a1243e16 100644
--- a/roomserver/state/state.go
+++ b/roomserver/state/state.go
@@ -18,6 +18,7 @@ package state
 
 import (
 	"context"
+	"database/sql"
 	"fmt"
 	"sort"
 	"time"
@@ -34,13 +35,15 @@ type StateResolution struct {
 	db       storage.Database
 	roomInfo types.RoomInfo
 	events   map[types.EventNID]*gomatrixserverlib.Event
+	txn      *sql.Tx // optional
 }
 
-func NewStateResolution(db storage.Database, roomInfo types.RoomInfo) StateResolution {
+func NewStateResolution(db storage.Database, roomInfo types.RoomInfo, tx *sql.Tx) StateResolution {
 	return StateResolution{
 		db:       db,
 		roomInfo: roomInfo,
 		events:   make(map[types.EventNID]*gomatrixserverlib.Event),
+		txn:      tx,
 	}
 }
 
@@ -549,7 +552,7 @@ func (v *StateResolution) CalculateAndStoreStateAfterEvents(
 		// 2) There weren't any prev_events for this event so the state is
 		// empty.
 		metrics.algorithm = "empty_state"
-		stateNID, err := v.db.AddState(ctx, v.roomInfo.RoomNID, nil, nil)
+		stateNID, err := v.db.AddState(ctx, v.txn, v.roomInfo.RoomNID, nil, nil)
 		if err != nil {
 			err = fmt.Errorf("v.db.AddState: %w", err)
 		}
@@ -581,7 +584,7 @@ func (v *StateResolution) CalculateAndStoreStateAfterEvents(
 			// add the state event as a block of size one to the end of the blocks.
 			metrics.algorithm = "single_delta"
 			stateNID, err := v.db.AddState(
-				ctx, v.roomInfo.RoomNID, stateBlockNIDs, []types.StateEntry{prevState.StateEntry},
+				ctx, v.txn, v.roomInfo.RoomNID, stateBlockNIDs, []types.StateEntry{prevState.StateEntry},
 			)
 			if err != nil {
 				err = fmt.Errorf("v.db.AddState: %w", err)
@@ -626,7 +629,7 @@ func (v *StateResolution) calculateAndStoreStateAfterManyEvents(
 	// previous state.
 	metrics.conflictLength = conflictLength
 	metrics.fullStateLength = len(state)
-	return metrics.stop(v.db.AddState(ctx, roomNID, nil, state))
+	return metrics.stop(v.db.AddState(ctx, v.txn, roomNID, nil, state))
 }
 
 func (v *StateResolution) calculateStateAfterManyEvents(
diff --git a/roomserver/storage/interface.go b/roomserver/storage/interface.go
index d2b0e75c..b3bc1188 100644
--- a/roomserver/storage/interface.go
+++ b/roomserver/storage/interface.go
@@ -16,6 +16,7 @@ package storage
 
 import (
 	"context"
+	"database/sql"
 
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/storage/shared"
@@ -32,6 +33,7 @@ type Database interface {
 	// Store the room state at an event in the database
 	AddState(
 		ctx context.Context,
+		txn *sql.Tx,
 		roomNID types.RoomNID,
 		stateBlockNIDs []types.StateBlockNID,
 		state []types.StateEntry,
diff --git a/roomserver/storage/shared/latest_events_updater.go b/roomserver/storage/shared/latest_events_updater.go
index 36865081..c2a9b313 100644
--- a/roomserver/storage/shared/latest_events_updater.go
+++ b/roomserver/storage/shared/latest_events_updater.go
@@ -16,6 +16,7 @@ type LatestEventsUpdater struct {
 	latestEvents            []types.StateAtEventAndReference
 	lastEventIDSent         string
 	currentStateSnapshotNID types.StateSnapshotNID
+	Txn                     *sql.Tx
 }
 
 func rollback(txn *sql.Tx) {
@@ -46,7 +47,7 @@ func NewLatestEventsUpdater(ctx context.Context, d *Database, txn *sql.Tx, roomI
 		}
 	}
 	return &LatestEventsUpdater{
-		transaction{ctx, txn}, d, roomInfo, stateAndRefs, lastEventIDSent, currentStateSnapshotNID,
+		transaction{ctx, txn}, d, roomInfo, stateAndRefs, lastEventIDSent, currentStateSnapshotNID, txn,
 	}, nil
 }
 
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index 24b48772..1689b882 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -137,11 +137,12 @@ func (d *Database) RoomInfo(ctx context.Context, roomID string) (*types.RoomInfo
 
 func (d *Database) AddState(
 	ctx context.Context,
+	txn *sql.Tx,
 	roomNID types.RoomNID,
 	stateBlockNIDs []types.StateBlockNID,
 	state []types.StateEntry,
 ) (stateNID types.StateSnapshotNID, err error) {
-	err = d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+	err = d.Writer.Do(d.DB, txn, func(txn *sql.Tx) error {
 		if len(state) > 0 {
 			var stateBlockNID types.StateBlockNID
 			stateBlockNID, err = d.StateBlockTable.BulkInsertStateData(ctx, txn, state)