Merge branch 'main' into neilalexander/jassuko

clientapi/routing/admin.go

@@ -1,6 +1,7 @@
 package routing
 
 import (
+	"context"
 	"encoding/json"
 	"net/http"
 
@@ -90,6 +91,37 @@ func AdminEvacuateUser(req *http.Request, cfg *config.ClientAPI, device *userapi
 	}
 }
 
+func AdminPurgeRoom(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, rsAPI roomserverAPI.ClientRoomserverAPI) util.JSONResponse {
+	vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+	if err != nil {
+		return util.ErrorResponse(err)
+	}
+	roomID, ok := vars["roomID"]
+	if !ok {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.MissingArgument("Expecting room ID."),
+		}
+	}
+	res := &roomserverAPI.PerformAdminPurgeRoomResponse{}
+	if err := rsAPI.PerformAdminPurgeRoom(
+		context.Background(),
+		&roomserverAPI.PerformAdminPurgeRoomRequest{
+			RoomID: roomID,
+		},
+		res,
+	); err != nil {
+		return util.ErrorResponse(err)
+	}
+	if err := res.Error; err != nil {
+		return err.JSONResponse()
+	}
+	return util.JSONResponse{
+		Code: 200,
+		JSON: res,
+	}
+}
+
 func AdminResetPassword(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, userAPI userapi.ClientUserAPI) util.JSONResponse {
 	vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
 	if err != nil {
@@ -138,3 +170,43 @@ func AdminResetPassword(req *http.Request, cfg *config.ClientAPI, device *userap
 		},
 	}
 }
+
+func AdminDownloadState(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, rsAPI roomserverAPI.ClientRoomserverAPI) util.JSONResponse {
+	vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+	if err != nil {
+		return util.ErrorResponse(err)
+	}
+	roomID, ok := vars["roomID"]
+	if !ok {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.MissingArgument("Expecting room ID."),
+		}
+	}
+	serverName, ok := vars["serverName"]
+	if !ok {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.MissingArgument("Expecting remote server name."),
+		}
+	}
+	res := &roomserverAPI.PerformAdminDownloadStateResponse{}
+	if err := rsAPI.PerformAdminDownloadState(
+		req.Context(),
+		&roomserverAPI.PerformAdminDownloadStateRequest{
+			UserID:     device.UserID,
+			RoomID:     roomID,
+			ServerName: gomatrixserverlib.ServerName(serverName),
+		},
+		res,
+	); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
+	if err := res.Error; err != nil {
+		return err.JSONResponse()
+	}
+	return util.JSONResponse{
+		Code: 200,
+		JSON: map[string]interface{}{},
+	}
+}

clientapi/routing/routing.go

@@ -155,12 +155,24 @@ func Setup(
 		}),
 	).Methods(http.MethodGet, http.MethodOptions)
 
+	dendriteAdminRouter.Handle("/admin/purgeRoom/{roomID}",
+		httputil.MakeAdminAPI("admin_purge_room", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			return AdminPurgeRoom(req, cfg, device, rsAPI)
+		}),
+	).Methods(http.MethodGet, http.MethodOptions)
+
 	dendriteAdminRouter.Handle("/admin/resetPassword/{localpart}",
 		httputil.MakeAdminAPI("admin_reset_password", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
 			return AdminResetPassword(req, cfg, device, userAPI)
 		}),
 	).Methods(http.MethodPost, http.MethodOptions)
 
+	dendriteAdminRouter.Handle("/admin/downloadState/{serverName}/{roomID}",
+		httputil.MakeAdminAPI("admin_download_state", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			return AdminDownloadState(req, cfg, device, rsAPI)
+		}),
+	).Methods(http.MethodGet, http.MethodOptions)
+
 	// server notifications
 	if cfg.Matrix.ServerNotices.Enabled {
 		logrus.Info("Enabling server notices at /_synapse/admin/v1/send_server_notice")

federationapi/consumers/roomserver.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
+	"github.com/sirupsen/logrus"
 	log "github.com/sirupsen/logrus"
 
 	"github.com/matrix-org/dendrite/federationapi/queue"
@@ -110,6 +111,14 @@ func (s *OutputRoomEventConsumer) onMessage(ctx context.Context, msgs []*nats.Ms
 			return false
 		}
 
+	case api.OutputTypePurgeRoom:
+		log.WithField("room_id", output.PurgeRoom.RoomID).Warn("Purging room from federation API")
+		if err := s.db.PurgeRoom(ctx, output.PurgeRoom.RoomID); err != nil {
+			logrus.WithField("room_id", output.PurgeRoom.RoomID).WithError(err).Error("Failed to purge room from federation API")
+		} else {
+			logrus.WithField("room_id", output.PurgeRoom.RoomID).Warn("Room purged from federation API")
+		}
+
 	default:
 		log.WithField("type", output.Type).Debug(
 			"roomserver output log: ignoring unknown output type",

federationapi/storage/interface.go

@@ -73,4 +73,6 @@ type Database interface {
 	GetNotaryKeys(ctx context.Context, serverName gomatrixserverlib.ServerName, optKeyIDs []gomatrixserverlib.KeyID) ([]gomatrixserverlib.ServerKeys, error)
 	// DeleteExpiredEDUs cleans up expired EDUs
 	DeleteExpiredEDUs(ctx context.Context) error
+
+	PurgeRoom(ctx context.Context, roomID string) error
 }

federationapi/storage/postgres/joined_hosts_table.go

@@ -66,6 +66,9 @@ const selectAllJoinedHostsSQL = "" +
 const selectJoinedHostsForRoomsSQL = "" +
 	"SELECT DISTINCT server_name FROM federationsender_joined_hosts WHERE room_id = ANY($1)"
 
+const purgeJoinedHostsSQL = "" +
+	"DELETE FROM federationsender_joined_hosts WHERE room_id = $1"
+
 type joinedHostsStatements struct {
 	db                            *sql.DB
 	insertJoinedHostsStmt         *sql.Stmt
@@ -74,6 +77,7 @@ type joinedHostsStatements struct {
 	selectJoinedHostsStmt         *sql.Stmt
 	selectAllJoinedHostsStmt      *sql.Stmt
 	selectJoinedHostsForRoomsStmt *sql.Stmt
+	purgeJoinedHostsStmt          *sql.Stmt
 }
 
 func NewPostgresJoinedHostsTable(db *sql.DB) (s *joinedHostsStatements, err error) {
@@ -102,6 +106,9 @@ func NewPostgresJoinedHostsTable(db *sql.DB) (s *joinedHostsStatements, err erro
 	if s.selectJoinedHostsForRoomsStmt, err = s.db.Prepare(selectJoinedHostsForRoomsSQL); err != nil {
 		return
 	}
+	if s.purgeJoinedHostsStmt, err = s.db.Prepare(purgeJoinedHostsSQL); err != nil {
+		return
+	}
 	return
 }
 
@@ -210,3 +217,10 @@ func joinedHostsFromStmt(
 
 	return result, rows.Err()
 }
+
+func (s *joinedHostsStatements) PurgeJoinedHosts(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeJoinedHostsStmt).ExecContext(ctx, roomID)
+	return err
+}

federationapi/storage/shared/storage.go

@@ -253,3 +253,18 @@ func (d *Database) GetNotaryKeys(
 	})
 	return sks, err
 }
+
+func (d *Database) PurgeRoom(ctx context.Context, roomID string) error {
+	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+		if err := d.FederationJoinedHosts.PurgeJoinedHosts(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge joined hosts: %w", err)
+		}
+		if err := d.FederationInboundPeeks.DeleteInboundPeeks(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge inbound peeks: %w", err)
+		}
+		if err := d.FederationOutboundPeeks.DeleteOutboundPeeks(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge outbound peeks: %w", err)
+		}
+		return nil
+	})
+}

federationapi/storage/sqlite3/joined_hosts_table.go

@@ -18,6 +18,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	"strings"
 
 	"github.com/matrix-org/dendrite/federationapi/types"
@@ -217,3 +218,9 @@ func joinedHostsFromStmt(
 
 	return result, nil
 }
+
+func (s *joinedHostsStatements) PurgeJoinedHosts(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

federationapi/storage/tables/interface.go

@@ -59,6 +59,7 @@ type FederationJoinedHosts interface {
 	SelectJoinedHosts(ctx context.Context, roomID string) ([]types.JoinedHost, error)
 	SelectAllJoinedHosts(ctx context.Context) ([]gomatrixserverlib.ServerName, error)
 	SelectJoinedHostsForRooms(ctx context.Context, roomIDs []string) ([]gomatrixserverlib.ServerName, error)
+	PurgeJoinedHosts(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type FederationBlacklist interface {

roomserver/api/api.go

@@ -150,6 +150,8 @@ type ClientRoomserverAPI interface {
 	PerformRoomUpgrade(ctx context.Context, req *PerformRoomUpgradeRequest, resp *PerformRoomUpgradeResponse) error
 	PerformAdminEvacuateRoom(ctx context.Context, req *PerformAdminEvacuateRoomRequest, res *PerformAdminEvacuateRoomResponse) error
 	PerformAdminEvacuateUser(ctx context.Context, req *PerformAdminEvacuateUserRequest, res *PerformAdminEvacuateUserResponse) error
+	PerformAdminPurgeRoom(ctx context.Context, req *PerformAdminPurgeRoomRequest, res *PerformAdminPurgeRoomResponse) error
+	PerformAdminDownloadState(ctx context.Context, req *PerformAdminDownloadStateRequest, res *PerformAdminDownloadStateResponse) error
 	PerformPeek(ctx context.Context, req *PerformPeekRequest, res *PerformPeekResponse) error
 	PerformUnpeek(ctx context.Context, req *PerformUnpeekRequest, res *PerformUnpeekResponse) error
 	PerformInvite(ctx context.Context, req *PerformInviteRequest, res *PerformInviteResponse) error

roomserver/api/api_trace.go

@@ -131,6 +131,26 @@ func (t *RoomserverInternalAPITrace) PerformAdminEvacuateUser(
 	return err
 }
 
+func (t *RoomserverInternalAPITrace) PerformAdminPurgeRoom(
+	ctx context.Context,
+	req *PerformAdminPurgeRoomRequest,
+	res *PerformAdminPurgeRoomResponse,
+) error {
+	err := t.Impl.PerformAdminPurgeRoom(ctx, req, res)
+	util.GetLogger(ctx).WithError(err).Infof("PerformAdminPurgeRoom req=%+v res=%+v", js(req), js(res))
+	return err
+}
+
+func (t *RoomserverInternalAPITrace) PerformAdminDownloadState(
+	ctx context.Context,
+	req *PerformAdminDownloadStateRequest,
+	res *PerformAdminDownloadStateResponse,
+) error {
+	err := t.Impl.PerformAdminDownloadState(ctx, req, res)
+	util.GetLogger(ctx).WithError(err).Infof("PerformAdminDownloadState req=%+v res=%+v", js(req), js(res))
+	return err
+}
+
 func (t *RoomserverInternalAPITrace) PerformInboundPeek(
 	ctx context.Context,
 	req *PerformInboundPeekRequest,

roomserver/api/output.go

@@ -55,6 +55,8 @@ const (
 	OutputTypeNewInboundPeek OutputType = "new_inbound_peek"
 	// OutputTypeRetirePeek indicates that the kafka event is an OutputRetirePeek
 	OutputTypeRetirePeek OutputType = "retire_peek"
+	// OutputTypePurgeRoom indicates the event is an OutputPurgeRoom
+	OutputTypePurgeRoom OutputType = "purge_room"
 )
 
 // An OutputEvent is an entry in the roomserver output kafka log.
@@ -78,6 +80,8 @@ type OutputEvent struct {
 	NewInboundPeek *OutputNewInboundPeek `json:"new_inbound_peek,omitempty"`
 	// The content of event with type OutputTypeRetirePeek
 	RetirePeek *OutputRetirePeek `json:"retire_peek,omitempty"`
+	// The content of the event with type OutputPurgeRoom
+	PurgeRoom *OutputPurgeRoom `json:"purge_room,omitempty"`
 }
 
 // Type of the OutputNewRoomEvent.
@@ -257,3 +261,7 @@ type OutputRetirePeek struct {
 	UserID   string
 	DeviceID string
 }
+
+type OutputPurgeRoom struct {
+	RoomID string
+}

roomserver/api/perform.go

@@ -234,3 +234,21 @@ type PerformAdminEvacuateUserResponse struct {
 	Affected []string `json:"affected"`
 	Error    *PerformError
 }
+
+type PerformAdminPurgeRoomRequest struct {
+	RoomID string `json:"room_id"`
+}
+
+type PerformAdminPurgeRoomResponse struct {
+	Error *PerformError `json:"error,omitempty"`
+}
+
+type PerformAdminDownloadStateRequest struct {
+	RoomID     string                       `json:"room_id"`
+	UserID     string                       `json:"user_id"`
+	ServerName gomatrixserverlib.ServerName `json:"server_name"`
+}
+
+type PerformAdminDownloadStateResponse struct {
+	Error *PerformError `json:"error,omitempty"`
+}

roomserver/internal/perform/perform_admin.go

@@ -28,6 +28,7 @@ import (
 	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/sirupsen/logrus"
 )
 
 type Admin struct {
@@ -231,3 +232,181 @@ func (r *Admin) PerformAdminEvacuateUser(
 	}
 	return nil
 }
+
+func (r *Admin) PerformAdminPurgeRoom(
+	ctx context.Context,
+	req *api.PerformAdminPurgeRoomRequest,
+	res *api.PerformAdminPurgeRoomResponse,
+) error {
+	if _, _, err := gomatrixserverlib.SplitID('!', req.RoomID); err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("Malformed room ID: %s", err),
+		}
+		return nil
+	}
+
+	logrus.WithField("room_id", req.RoomID).Warn("Purging room from roomserver")
+	if err := r.DB.PurgeRoom(ctx, req.RoomID); err != nil {
+		logrus.WithField("room_id", req.RoomID).WithError(err).Warn("Failed to purge room from roomserver")
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  err.Error(),
+		}
+		return nil
+	} else {
+		logrus.WithField("room_id", req.RoomID).Warn("Room purged from roomserver")
+	}
+
+	return r.Inputer.OutputProducer.ProduceRoomEvents(req.RoomID, []api.OutputEvent{
+		{
+			Type: api.OutputTypePurgeRoom,
+			PurgeRoom: &api.OutputPurgeRoom{
+				RoomID: req.RoomID,
+			},
+		},
+	})
+}
+
+func (r *Admin) PerformAdminDownloadState(
+	ctx context.Context,
+	req *api.PerformAdminDownloadStateRequest,
+	res *api.PerformAdminDownloadStateResponse,
+) error {
+	roomInfo, err := r.DB.RoomInfo(ctx, req.RoomID)
+	if err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("r.DB.RoomInfo: %s", err),
+		}
+		return nil
+	}
+
+	if roomInfo == nil || roomInfo.IsStub() {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("room %q not found", req.RoomID),
+		}
+		return nil
+	}
+
+	fwdExtremities, _, depth, err := r.DB.LatestEventIDs(ctx, roomInfo.RoomNID)
+	if err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("r.DB.LatestEventIDs: %s", err),
+		}
+		return nil
+	}
+
+	authEventMap := map[string]*gomatrixserverlib.Event{}
+	stateEventMap := map[string]*gomatrixserverlib.Event{}
+
+	for _, fwdExtremity := range fwdExtremities {
+		var state gomatrixserverlib.RespState
+		state, err = r.Inputer.FSAPI.LookupState(ctx, req.ServerName, req.RoomID, fwdExtremity.EventID, roomInfo.RoomVersion)
+		if err != nil {
+			res.Error = &api.PerformError{
+				Code: api.PerformErrorBadRequest,
+				Msg:  fmt.Sprintf("r.Inputer.FSAPI.LookupState (%q): %s", fwdExtremity.EventID, err),
+			}
+			return nil
+		}
+		for _, authEvent := range state.AuthEvents.UntrustedEvents(roomInfo.RoomVersion) {
+			if err = authEvent.VerifyEventSignatures(ctx, r.Inputer.KeyRing); err != nil {
+				continue
+			}
+			authEventMap[authEvent.EventID()] = authEvent
+		}
+		for _, stateEvent := range state.StateEvents.UntrustedEvents(roomInfo.RoomVersion) {
+			if err = stateEvent.VerifyEventSignatures(ctx, r.Inputer.KeyRing); err != nil {
+				continue
+			}
+			stateEventMap[stateEvent.EventID()] = stateEvent
+		}
+	}
+
+	authEvents := make([]*gomatrixserverlib.HeaderedEvent, 0, len(authEventMap))
+	stateEvents := make([]*gomatrixserverlib.HeaderedEvent, 0, len(stateEventMap))
+	stateIDs := make([]string, 0, len(stateEventMap))
+
+	for _, authEvent := range authEventMap {
+		authEvents = append(authEvents, authEvent.Headered(roomInfo.RoomVersion))
+	}
+	for _, stateEvent := range stateEventMap {
+		stateEvents = append(stateEvents, stateEvent.Headered(roomInfo.RoomVersion))
+		stateIDs = append(stateIDs, stateEvent.EventID())
+	}
+
+	builder := &gomatrixserverlib.EventBuilder{
+		Type:    "org.matrix.dendrite.state_download",
+		Sender:  req.UserID,
+		RoomID:  req.RoomID,
+		Content: gomatrixserverlib.RawJSON("{}"),
+	}
+
+	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
+	if err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("gomatrixserverlib.StateNeededForEventBuilder: %s", err),
+		}
+		return nil
+	}
+
+	queryRes := &api.QueryLatestEventsAndStateResponse{
+		RoomExists:   true,
+		RoomVersion:  roomInfo.RoomVersion,
+		LatestEvents: fwdExtremities,
+		StateEvents:  stateEvents,
+		Depth:        depth,
+	}
+
+	ev, err := eventutil.BuildEvent(ctx, builder, r.Cfg.Matrix, time.Now(), &eventsNeeded, queryRes)
+	if err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("eventutil.BuildEvent: %s", err),
+		}
+		return nil
+	}
+
+	inputReq := &api.InputRoomEventsRequest{
+		Asynchronous: false,
+	}
+	inputRes := &api.InputRoomEventsResponse{}
+
+	for _, authEvent := range append(authEvents, stateEvents...) {
+		inputReq.InputRoomEvents = append(inputReq.InputRoomEvents, api.InputRoomEvent{
+			Kind:   api.KindOutlier,
+			Event:  authEvent,
+			Origin: authEvent.Origin(),
+		})
+	}
+
+	inputReq.InputRoomEvents = append(inputReq.InputRoomEvents, api.InputRoomEvent{
+		Kind:          api.KindNew,
+		Event:         ev,
+		Origin:        r.Cfg.Matrix.ServerName,
+		HasState:      true,
+		StateEventIDs: stateIDs,
+		SendAsServer:  string(r.Cfg.Matrix.ServerName),
+	})
+
+	if err := r.Inputer.InputRoomEvents(ctx, inputReq, inputRes); err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("r.Inputer.InputRoomEvents: %s", err),
+		}
+		return nil
+	}
+
+	if inputRes.ErrMsg != "" {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  inputRes.ErrMsg,
+		}
+	}
+
+	return nil
+}

roomserver/inthttp/client.go

@@ -27,18 +27,20 @@ const (
 	RoomserverInputRoomEventsPath = "/roomserver/inputRoomEvents"
 
 	// Perform operations
-	RoomserverPerformInvitePath            = "/roomserver/performInvite"
-	RoomserverPerformPeekPath              = "/roomserver/performPeek"
-	RoomserverPerformUnpeekPath            = "/roomserver/performUnpeek"
-	RoomserverPerformRoomUpgradePath       = "/roomserver/performRoomUpgrade"
-	RoomserverPerformJoinPath              = "/roomserver/performJoin"
-	RoomserverPerformLeavePath             = "/roomserver/performLeave"
-	RoomserverPerformBackfillPath          = "/roomserver/performBackfill"
-	RoomserverPerformPublishPath           = "/roomserver/performPublish"
-	RoomserverPerformInboundPeekPath       = "/roomserver/performInboundPeek"
-	RoomserverPerformForgetPath            = "/roomserver/performForget"
-	RoomserverPerformAdminEvacuateRoomPath = "/roomserver/performAdminEvacuateRoom"
-	RoomserverPerformAdminEvacuateUserPath = "/roomserver/performAdminEvacuateUser"
+	RoomserverPerformInvitePath             = "/roomserver/performInvite"
+	RoomserverPerformPeekPath               = "/roomserver/performPeek"
+	RoomserverPerformUnpeekPath             = "/roomserver/performUnpeek"
+	RoomserverPerformRoomUpgradePath        = "/roomserver/performRoomUpgrade"
+	RoomserverPerformJoinPath               = "/roomserver/performJoin"
+	RoomserverPerformLeavePath              = "/roomserver/performLeave"
+	RoomserverPerformBackfillPath           = "/roomserver/performBackfill"
+	RoomserverPerformPublishPath            = "/roomserver/performPublish"
+	RoomserverPerformInboundPeekPath        = "/roomserver/performInboundPeek"
+	RoomserverPerformForgetPath             = "/roomserver/performForget"
+	RoomserverPerformAdminEvacuateRoomPath  = "/roomserver/performAdminEvacuateRoom"
+	RoomserverPerformAdminEvacuateUserPath  = "/roomserver/performAdminEvacuateUser"
+	RoomserverPerformAdminPurgeRoomPath     = "/roomserver/performAdminPurgeRoom"
+	RoomserverPerformAdminDownloadStatePath = "/roomserver/performAdminDownloadState"
 
 	// Query operations
 	RoomserverQueryLatestEventsAndStatePath    = "/roomserver/queryLatestEventsAndState"
@@ -261,6 +263,17 @@ func (h *httpRoomserverInternalAPI) PerformAdminEvacuateRoom(
 	)
 }
 
+func (h *httpRoomserverInternalAPI) PerformAdminDownloadState(
+	ctx context.Context,
+	request *api.PerformAdminDownloadStateRequest,
+	response *api.PerformAdminDownloadStateResponse,
+) error {
+	return httputil.CallInternalRPCAPI(
+		"PerformAdminDownloadState", h.roomserverURL+RoomserverPerformAdminDownloadStatePath,
+		h.httpClient, ctx, request, response,
+	)
+}
+
 func (h *httpRoomserverInternalAPI) PerformAdminEvacuateUser(
 	ctx context.Context,
 	request *api.PerformAdminEvacuateUserRequest,
@@ -272,6 +285,17 @@ func (h *httpRoomserverInternalAPI) PerformAdminEvacuateUser(
 	)
 }
 
+func (h *httpRoomserverInternalAPI) PerformAdminPurgeRoom(
+	ctx context.Context,
+	request *api.PerformAdminPurgeRoomRequest,
+	response *api.PerformAdminPurgeRoomResponse,
+) error {
+	return httputil.CallInternalRPCAPI(
+		"PerformAdminPurgeRoom", h.roomserverURL+RoomserverPerformAdminPurgeRoomPath,
+		h.httpClient, ctx, request, response,
+	)
+}
+
 // QueryLatestEventsAndState implements RoomserverQueryAPI
 func (h *httpRoomserverInternalAPI) QueryLatestEventsAndState(
 	ctx context.Context,

roomserver/inthttp/server.go

@@ -65,6 +65,16 @@ func AddRoutes(r api.RoomserverInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalRPCAPI("RoomserverPerformAdminEvacuateUser", r.PerformAdminEvacuateUser),
 	)
 
+	internalAPIMux.Handle(
+		RoomserverPerformAdminPurgeRoomPath,
+		httputil.MakeInternalRPCAPI("RoomserverPerformAdminPurgeRoom", r.PerformAdminPurgeRoom),
+	)
+
+	internalAPIMux.Handle(
+		RoomserverPerformAdminDownloadStatePath,
+		httputil.MakeInternalRPCAPI("RoomserverPerformAdminDownloadState", r.PerformAdminDownloadState),
+	)
+
 	internalAPIMux.Handle(
 		RoomserverQueryPublishedRoomsPath,
 		httputil.MakeInternalRPCAPI("RoomserverQueryPublishedRooms", r.QueryPublishedRooms),

roomserver/storage/interface.go

@@ -170,4 +170,5 @@ type Database interface {
 	ForgetRoom(ctx context.Context, userID, roomID string, forget bool) error
 
 	GetHistoryVisibilityState(ctx context.Context, roomInfo *types.RoomInfo, eventID string, domain string) ([]*gomatrixserverlib.Event, error)
+	PurgeRoom(ctx context.Context, roomID string) error
 }

roomserver/storage/postgres/purge_statements.go

@@ -0,0 +1,159 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const purgeEventJSONSQL = "" +
+	"DELETE FROM roomserver_event_json WHERE event_nid = ANY(" +
+	"	SELECT event_nid FROM roomserver_events WHERE room_nid = $1" +
+	")"
+
+const purgeEventsSQL = "" +
+	"DELETE FROM roomserver_events WHERE room_nid = $1"
+
+const purgeInvitesSQL = "" +
+	"DELETE FROM roomserver_invites WHERE room_nid = $1"
+
+const purgeMembershipsSQL = "" +
+	"DELETE FROM roomserver_membership WHERE room_nid = $1"
+
+const purgePreviousEventsSQL = "" +
+	"DELETE FROM roomserver_previous_events WHERE event_nids && ANY(" +
+	"	SELECT ARRAY_AGG(event_nid) FROM roomserver_events WHERE room_nid = $1" +
+	")"
+
+const purgePublishedSQL = "" +
+	"DELETE FROM roomserver_published WHERE room_id = $1"
+
+const purgeRedactionsSQL = "" +
+	"DELETE FROM roomserver_redactions WHERE redaction_event_id = ANY(" +
+	"	SELECT event_id FROM roomserver_events WHERE room_nid = $1" +
+	")"
+
+const purgeRoomAliasesSQL = "" +
+	"DELETE FROM roomserver_room_aliases WHERE room_id = $1"
+
+const purgeRoomSQL = "" +
+	"DELETE FROM roomserver_rooms WHERE room_nid = $1"
+
+const purgeStateBlockEntriesSQL = "" +
+	"DELETE FROM roomserver_state_block WHERE state_block_nid = ANY(" +
+	"	SELECT DISTINCT UNNEST(state_block_nids) FROM roomserver_state_snapshots WHERE room_nid = $1" +
+	")"
+
+const purgeStateSnapshotEntriesSQL = "" +
+	"DELETE FROM roomserver_state_snapshots WHERE room_nid = $1"
+
+type purgeStatements struct {
+	purgeEventJSONStmt            *sql.Stmt
+	purgeEventsStmt               *sql.Stmt
+	purgeInvitesStmt              *sql.Stmt
+	purgeMembershipsStmt          *sql.Stmt
+	purgePreviousEventsStmt       *sql.Stmt
+	purgePublishedStmt            *sql.Stmt
+	purgeRedactionStmt            *sql.Stmt
+	purgeRoomAliasesStmt          *sql.Stmt
+	purgeRoomStmt                 *sql.Stmt
+	purgeStateBlockEntriesStmt    *sql.Stmt
+	purgeStateSnapshotEntriesStmt *sql.Stmt
+}
+
+func PreparePurgeStatements(db *sql.DB) (*purgeStatements, error) {
+	s := &purgeStatements{}
+
+	return s, sqlutil.StatementList{
+		{&s.purgeEventJSONStmt, purgeEventJSONSQL},
+		{&s.purgeEventsStmt, purgeEventsSQL},
+		{&s.purgeInvitesStmt, purgeInvitesSQL},
+		{&s.purgeMembershipsStmt, purgeMembershipsSQL},
+		{&s.purgePublishedStmt, purgePublishedSQL},
+		{&s.purgePreviousEventsStmt, purgePreviousEventsSQL},
+		{&s.purgeRedactionStmt, purgeRedactionsSQL},
+		{&s.purgeRoomAliasesStmt, purgeRoomAliasesSQL},
+		{&s.purgeRoomStmt, purgeRoomSQL},
+		{&s.purgeStateBlockEntriesStmt, purgeStateBlockEntriesSQL},
+		{&s.purgeStateSnapshotEntriesStmt, purgeStateSnapshotEntriesSQL},
+	}.Prepare(db)
+}
+
+func (s *purgeStatements) PurgeEventJSONs(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeEventJSONStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeEvents(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeEventsStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeInvites(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeInvitesStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeMemberships(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeMembershipsStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgePreviousEvents(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgePreviousEventsStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgePublished(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgePublishedStmt).ExecContext(ctx, roomID)
+	return err
+}
+
+func (s *purgeStatements) PurgeRedactions(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeRedactionStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeRoomAliases(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeRoomAliasesStmt).ExecContext(ctx, roomID)
+	return err
+}
+
+func (s *purgeStatements) PurgeRoom(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeRoomStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeStateBlocks(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeStateBlockEntriesStmt).ExecContext(ctx, roomNID)
+	return err
+}
+
+func (s *purgeStatements) PurgeStateSnapshots(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeStateSnapshotEntriesStmt).ExecContext(ctx, roomNID)
+	return err
+}

roomserver/storage/postgres/rooms_table.go

@@ -58,6 +58,9 @@ const insertRoomNIDSQL = "" +
 const selectRoomNIDSQL = "" +
 	"SELECT room_nid FROM roomserver_rooms WHERE room_id = $1"
 
+const selectRoomNIDForUpdateSQL = "" +
+	"SELECT room_nid FROM roomserver_rooms WHERE room_id = $1 FOR UPDATE"
+
 const selectLatestEventNIDsSQL = "" +
 	"SELECT latest_event_nids, state_snapshot_nid FROM roomserver_rooms WHERE room_nid = $1"
 
@@ -85,6 +88,7 @@ const bulkSelectRoomNIDsSQL = "" +
 type roomStatements struct {
 	insertRoomNIDStmt                  *sql.Stmt
 	selectRoomNIDStmt                  *sql.Stmt
+	selectRoomNIDForUpdateStmt         *sql.Stmt
 	selectLatestEventNIDsStmt          *sql.Stmt
 	selectLatestEventNIDsForUpdateStmt *sql.Stmt
 	updateLatestEventNIDsStmt          *sql.Stmt
@@ -106,6 +110,7 @@ func PrepareRoomsTable(db *sql.DB) (tables.Rooms, error) {
 	return s, sqlutil.StatementList{
 		{&s.insertRoomNIDStmt, insertRoomNIDSQL},
 		{&s.selectRoomNIDStmt, selectRoomNIDSQL},
+		{&s.selectRoomNIDForUpdateStmt, selectRoomNIDForUpdateSQL},
 		{&s.selectLatestEventNIDsStmt, selectLatestEventNIDsSQL},
 		{&s.selectLatestEventNIDsForUpdateStmt, selectLatestEventNIDsForUpdateSQL},
 		{&s.updateLatestEventNIDsStmt, updateLatestEventNIDsSQL},
@@ -169,6 +174,15 @@ func (s *roomStatements) SelectRoomNID(
 	return types.RoomNID(roomNID), err
 }
 
+func (s *roomStatements) SelectRoomNIDForUpdate(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (types.RoomNID, error) {
+	var roomNID int64
+	stmt := sqlutil.TxStmt(txn, s.selectRoomNIDForUpdateStmt)
+	err := stmt.QueryRowContext(ctx, roomID).Scan(&roomNID)
+	return types.RoomNID(roomNID), err
+}
+
 func (s *roomStatements) SelectLatestEventNIDs(
 	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
 ) ([]types.EventNID, types.StateSnapshotNID, error) {

roomserver/storage/postgres/storage.go

@@ -189,6 +189,10 @@ func (d *Database) prepare(db *sql.DB, writer sqlutil.Writer, cache caching.Room
 	if err != nil {
 		return err
 	}
+	purge, err := PreparePurgeStatements(db)
+	if err != nil {
+		return err
+	}
 	d.Database = shared.Database{
 		DB:                  db,
 		Cache:               cache,
@@ -206,6 +210,7 @@ func (d *Database) prepare(db *sql.DB, writer sqlutil.Writer, cache caching.Room
 		MembershipTable:     membership,
 		PublishedTable:      published,
 		RedactionsTable:     redactions,
+		Purge:               purge,
 	}
 	return nil
 }

roomserver/storage/shared/storage.go

@@ -42,6 +42,7 @@ type Database struct {
 	MembershipTable     tables.Membership
 	PublishedTable      tables.Published
 	RedactionsTable     tables.Redactions
+	Purge               tables.Purge
 	GetRoomUpdaterFn    func(ctx context.Context, roomInfo *types.RoomInfo) (*RoomUpdater, error)
 }
 
@@ -1362,6 +1363,57 @@ func (d *Database) ForgetRoom(ctx context.Context, userID, roomID string, forget
 	})
 }
 
+// PurgeRoom removes all information about a given room from the roomserver.
+// For large rooms this operation may take a considerable amount of time.
+func (d *Database) PurgeRoom(ctx context.Context, roomID string) error {
+	if d.Purge == nil {
+		return fmt.Errorf("not supported on this database engine")
+	}
+	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+		roomNID, err := d.RoomsTable.SelectRoomNIDForUpdate(ctx, txn, roomID)
+		if err != nil {
+			if err == sql.ErrNoRows {
+				return nil
+			}
+			return fmt.Errorf("failed to lock the room: %w", err)
+		}
+		if err := d.Purge.PurgeStateBlocks(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge state blocks: %w", err)
+		}
+		if err := d.Purge.PurgeStateSnapshots(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge state blocks: %w", err)
+		}
+		if err := d.Purge.PurgeInvites(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge invites: %w", err)
+		}
+		if err := d.Purge.PurgeMemberships(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge memberships: %w", err)
+		}
+		if err := d.Purge.PurgeRoomAliases(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge room aliases: %w", err)
+		}
+		if err := d.Purge.PurgePublished(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge published: %w", err)
+		}
+		if err := d.Purge.PurgePreviousEvents(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge previous events: %w", err)
+		}
+		if err := d.Purge.PurgeEventJSONs(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge event JSONs: %w", err)
+		}
+		if err := d.Purge.PurgeRedactions(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge redactions: %w", err)
+		}
+		if err := d.Purge.PurgeEvents(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge events: %w", err)
+		}
+		if err := d.Purge.PurgeRoom(ctx, txn, roomNID); err != nil {
+			return fmt.Errorf("failed to purge room: %w", err)
+		}
+		return nil
+	})
+}
+
 // FIXME TODO: Remove all this - horrible dupe with roomserver/state. Can't use the original impl because of circular loops
 // it should live in this package!
 

roomserver/storage/sqlite3/rooms_table.go

@@ -169,6 +169,12 @@ func (s *roomStatements) SelectRoomNID(
 	return types.RoomNID(roomNID), err
 }
 
+func (s *roomStatements) SelectRoomNIDForUpdate(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (types.RoomNID, error) {
+	return 0, fmt.Errorf("not supported on SQLite")
+}
+
 func (s *roomStatements) SelectLatestEventNIDs(
 	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
 ) ([]types.EventNID, types.StateSnapshotNID, error) {

roomserver/storage/tables/interface.go

@@ -72,6 +72,7 @@ type Events interface {
 type Rooms interface {
 	InsertRoomNID(ctx context.Context, txn *sql.Tx, roomID string, roomVersion gomatrixserverlib.RoomVersion) (types.RoomNID, error)
 	SelectRoomNID(ctx context.Context, txn *sql.Tx, roomID string) (types.RoomNID, error)
+	SelectRoomNIDForUpdate(ctx context.Context, txn *sql.Tx, roomID string) (types.RoomNID, error)
 	SelectLatestEventNIDs(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) ([]types.EventNID, types.StateSnapshotNID, error)
 	SelectLatestEventsNIDsForUpdate(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) ([]types.EventNID, types.EventNID, types.StateSnapshotNID, error)
 	UpdateLatestEventNIDs(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, eventNIDs []types.EventNID, lastEventSentNID types.EventNID, stateSnapshotNID types.StateSnapshotNID) error
@@ -171,6 +172,20 @@ type Redactions interface {
 	MarkRedactionValidated(ctx context.Context, txn *sql.Tx, redactionEventID string, validated bool) error
 }
 
+type Purge interface {
+	PurgeEventJSONs(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeEvents(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeRoom(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeStateSnapshots(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeStateBlocks(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgePreviousEvents(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeInvites(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeMemberships(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgePublished(ctx context.Context, txn *sql.Tx, roomID string) error
+	PurgeRedactions(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) error
+	PurgeRoomAliases(ctx context.Context, txn *sql.Tx, roomID string) error
+}
+
 // StrippedEvent represents a stripped event for returning extracted content values.
 type StrippedEvent struct {
 	RoomID       string

syncapi/consumers/roomserver.go

@@ -31,6 +31,7 @@ import (
 	"github.com/matrix-org/dendrite/syncapi/types"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
+	"github.com/sirupsen/logrus"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -123,6 +124,8 @@ func (s *OutputRoomEventConsumer) onMessage(ctx context.Context, msgs []*nats.Ms
 		s.onRetirePeek(s.ctx, *output.RetirePeek)
 	case api.OutputTypeRedactedEvent:
 		err = s.onRedactEvent(s.ctx, *output.RedactedEvent)
+	case api.OutputTypePurgeRoom:
+		err = s.onPurgeRoom(s.ctx, *output.PurgeRoom)
 	default:
 		log.WithField("type", output.Type).Debug(
 			"roomserver output log: ignoring unknown output type",
@@ -434,6 +437,20 @@ func (s *OutputRoomEventConsumer) onRetirePeek(
 	s.notifier.OnRetirePeek(msg.RoomID, msg.UserID, msg.DeviceID, types.StreamingToken{PDUPosition: sp})
 }
 
+func (s *OutputRoomEventConsumer) onPurgeRoom(
+	ctx context.Context, req api.OutputPurgeRoom,
+) error {
+	logrus.WithField("room_id", req.RoomID).Warn("Purging room from sync API")
+
+	if err := s.db.PurgeRoom(ctx, req.RoomID); err != nil {
+		logrus.WithField("room_id", req.RoomID).WithError(err).Error("Failed to purge room from sync API")
+		return err
+	} else {
+		logrus.WithField("room_id", req.RoomID).Warn("Room purged from sync API")
+		return nil
+	}
+}
+
 func (s *OutputRoomEventConsumer) updateStateEvent(event *gomatrixserverlib.HeaderedEvent) (*gomatrixserverlib.HeaderedEvent, error) {
 	if event.StateKey() == nil {
 		return event, nil

syncapi/storage/interface.go

@@ -76,6 +76,7 @@ type Database interface {
 	// PurgeRoomState completely purges room state from the sync API. This is done when
 	// receiving an output event that completely resets the state.
 	PurgeRoomState(ctx context.Context, roomID string) error
+	PurgeRoom(ctx context.Context, roomID string) error
 	// GetStateEvent returns the Matrix state event of a given type for a given room with a given state key
 	// If no event could be found, returns nil
 	// If there was an issue during the retrieval, returns an error

syncapi/storage/postgres/backwards_extremities_table.go

@@ -47,10 +47,14 @@ const selectBackwardExtremitiesForRoomSQL = "" +
 const deleteBackwardExtremitySQL = "" +
 	"DELETE FROM syncapi_backward_extremities WHERE room_id = $1 AND prev_event_id = $2"
 
+const purgeBackwardExtremitiesSQL = "" +
+	"DELETE FROM syncapi_backward_extremities WHERE room_id = $1"
+
 type backwardExtremitiesStatements struct {
 	insertBackwardExtremityStmt          *sql.Stmt
 	selectBackwardExtremitiesForRoomStmt *sql.Stmt
 	deleteBackwardExtremityStmt          *sql.Stmt
+	purgeBackwardExtremitiesStmt         *sql.Stmt
 }
 
 func NewPostgresBackwardsExtremitiesTable(db *sql.DB) (tables.BackwardsExtremities, error) {
@@ -68,6 +72,9 @@ func NewPostgresBackwardsExtremitiesTable(db *sql.DB) (tables.BackwardsExtremiti
 	if s.deleteBackwardExtremityStmt, err = db.Prepare(deleteBackwardExtremitySQL); err != nil {
 		return nil, err
 	}
+	if s.purgeBackwardExtremitiesStmt, err = db.Prepare(purgeBackwardExtremitiesSQL); err != nil {
+		return nil, err
+	}
 	return s, nil
 }
 
@@ -106,3 +113,10 @@ func (s *backwardExtremitiesStatements) DeleteBackwardExtremity(
 	_, err = sqlutil.TxStmt(txn, s.deleteBackwardExtremityStmt).ExecContext(ctx, roomID, knownEventID)
 	return
 }
+
+func (s *backwardExtremitiesStatements) PurgeBackwardExtremities(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeBackwardExtremitiesStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/invites_table.go

@@ -62,11 +62,15 @@ const selectInviteEventsInRangeSQL = "" +
 const selectMaxInviteIDSQL = "" +
 	"SELECT MAX(id) FROM syncapi_invite_events"
 
+const purgeInvitesSQL = "" +
+	"DELETE FROM syncapi_invite_events WHERE room_id = $1"
+
 type inviteEventsStatements struct {
 	insertInviteEventStmt         *sql.Stmt
 	selectInviteEventsInRangeStmt *sql.Stmt
 	deleteInviteEventStmt         *sql.Stmt
 	selectMaxInviteIDStmt         *sql.Stmt
+	purgeInvitesStmt              *sql.Stmt
 }
 
 func NewPostgresInvitesTable(db *sql.DB) (tables.Invites, error) {
@@ -87,6 +91,9 @@ func NewPostgresInvitesTable(db *sql.DB) (tables.Invites, error) {
 	if s.selectMaxInviteIDStmt, err = db.Prepare(selectMaxInviteIDSQL); err != nil {
 		return nil, err
 	}
+	if s.purgeInvitesStmt, err = db.Prepare(purgeInvitesSQL); err != nil {
+		return nil, err
+	}
 	return s, nil
 }
 
@@ -173,3 +180,10 @@ func (s *inviteEventsStatements) SelectMaxInviteID(
 	}
 	return
 }
+
+func (s *inviteEventsStatements) PurgeInvites(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeInvitesStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/memberships_table.go

@@ -69,11 +69,15 @@ const selectHeroesSQL = "" +
 const selectMembershipBeforeSQL = "" +
 	"SELECT membership, topological_pos FROM syncapi_memberships WHERE room_id = $1 and user_id = $2 AND topological_pos <= $3 ORDER BY topological_pos DESC LIMIT 1"
 
+const purgeMembershipsSQL = "" +
+	"DELETE FROM syncapi_memberships WHERE room_id = $1"
+
 type membershipsStatements struct {
 	upsertMembershipStmt        *sql.Stmt
 	selectMembershipCountStmt   *sql.Stmt
 	selectHeroesStmt            *sql.Stmt
 	selectMembershipForUserStmt *sql.Stmt
+	purgeMembershipsStmt        *sql.Stmt
 }
 
 func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
@@ -87,6 +91,7 @@ func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
 		{&s.selectMembershipCountStmt, selectMembershipCountSQL},
 		{&s.selectHeroesStmt, selectHeroesSQL},
 		{&s.selectMembershipForUserStmt, selectMembershipBeforeSQL},
+		{&s.purgeMembershipsStmt, purgeMembershipsSQL},
 	}.Prepare(db)
 }
 
@@ -154,3 +159,10 @@ func (s *membershipsStatements) SelectMembershipForUser(
 	}
 	return membership, topologyPos, nil
 }
+
+func (s *membershipsStatements) PurgeMemberships(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeMembershipsStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/notification_data_table.go

@@ -35,6 +35,7 @@ func NewPostgresNotificationDataTable(db *sql.DB) (tables.NotificationData, erro
 		{&r.upsertRoomUnreadCounts, upsertRoomUnreadNotificationCountsSQL},
 		{&r.selectUserUnreadCounts, selectUserUnreadNotificationCountsSQL},
 		{&r.selectMaxID, selectMaxNotificationIDSQL},
+		{&r.purgeNotificationData, purgeNotificationDataSQL},
 	}.Prepare(db)
 }
 
@@ -42,6 +43,7 @@ type notificationDataStatements struct {
 	upsertRoomUnreadCounts *sql.Stmt
 	selectUserUnreadCounts *sql.Stmt
 	selectMaxID            *sql.Stmt
+	purgeNotificationData  *sql.Stmt
 }
 
 const notificationDataSchema = `
@@ -70,6 +72,9 @@ const selectUserUnreadNotificationCountsSQL = `SELECT
 
 const selectMaxNotificationIDSQL = `SELECT CASE COUNT(*) WHEN 0 THEN 0 ELSE MAX(id) END FROM syncapi_notification_data`
 
+const purgeNotificationDataSQL = "" +
+	"DELETE FROM syncapi_notification_data WHERE room_id = $1"
+
 func (r *notificationDataStatements) UpsertRoomUnreadCounts(ctx context.Context, txn *sql.Tx, userID, roomID string, notificationCount, highlightCount int) (pos types.StreamPosition, err error) {
 	err = sqlutil.TxStmt(txn, r.upsertRoomUnreadCounts).QueryRowContext(ctx, userID, roomID, notificationCount, highlightCount).Scan(&pos)
 	return
@@ -106,3 +111,10 @@ func (r *notificationDataStatements) SelectMaxID(ctx context.Context, txn *sql.T
 	err := sqlutil.TxStmt(txn, r.selectMaxID).QueryRowContext(ctx).Scan(&id)
 	return id, err
 }
+
+func (s *notificationDataStatements) PurgeNotificationData(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeNotificationData).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/output_room_events_table.go

@@ -166,6 +166,9 @@ const selectContextAfterEventSQL = "" +
 	" AND ( $7::text[] IS NULL OR NOT(type LIKE ANY($7)) )" +
 	" ORDER BY id ASC LIMIT $3"
 
+const purgeEventsSQL = "" +
+	"DELETE FROM syncapi_output_room_events WHERE room_id = $1"
+
 type outputRoomEventsStatements struct {
 	insertEventStmt               *sql.Stmt
 	selectEventsStmt              *sql.Stmt
@@ -180,6 +183,7 @@ type outputRoomEventsStatements struct {
 	selectContextEventStmt        *sql.Stmt
 	selectContextBeforeEventStmt  *sql.Stmt
 	selectContextAfterEventStmt   *sql.Stmt
+	purgeEventsStmt               *sql.Stmt
 }
 
 func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
@@ -215,6 +219,7 @@ func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
 		{&s.selectContextEventStmt, selectContextEventSQL},
 		{&s.selectContextBeforeEventStmt, selectContextBeforeEventSQL},
 		{&s.selectContextAfterEventStmt, selectContextAfterEventSQL},
+		{&s.purgeEventsStmt, purgeEventsSQL},
 	}.Prepare(db)
 }
 
@@ -632,3 +637,10 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 	}
 	return result, rows.Err()
 }
+
+func (s *outputRoomEventsStatements) PurgeEvents(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeEventsStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/output_room_events_topology_table.go

@@ -79,6 +79,9 @@ const selectStreamToTopologicalPositionAscSQL = "" +
 const selectStreamToTopologicalPositionDescSQL = "" +
 	"SELECT topological_position FROM syncapi_output_room_events_topology WHERE room_id = $1 AND stream_position <= $2 ORDER BY topological_position DESC LIMIT 1;"
 
+const purgeEventsTopologySQL = "" +
+	"DELETE FROM syncapi_output_room_events_topology WHERE room_id = $1"
+
 type outputRoomEventsTopologyStatements struct {
 	insertEventInTopologyStmt                 *sql.Stmt
 	selectEventIDsInRangeASCStmt              *sql.Stmt
@@ -87,6 +90,7 @@ type outputRoomEventsTopologyStatements struct {
 	selectMaxPositionInTopologyStmt           *sql.Stmt
 	selectStreamToTopologicalPositionAscStmt  *sql.Stmt
 	selectStreamToTopologicalPositionDescStmt *sql.Stmt
+	purgeEventsTopologyStmt                   *sql.Stmt
 }
 
 func NewPostgresTopologyTable(db *sql.DB) (tables.Topology, error) {
@@ -116,6 +120,9 @@ func NewPostgresTopologyTable(db *sql.DB) (tables.Topology, error) {
 	if s.selectStreamToTopologicalPositionDescStmt, err = db.Prepare(selectStreamToTopologicalPositionDescSQL); err != nil {
 		return nil, err
 	}
+	if s.purgeEventsTopologyStmt, err = db.Prepare(purgeEventsTopologySQL); err != nil {
+		return nil, err
+	}
 	return s, nil
 }
 
@@ -196,3 +203,10 @@ func (s *outputRoomEventsTopologyStatements) SelectMaxPositionInTopology(
 	err = s.selectMaxPositionInTopologyStmt.QueryRowContext(ctx, roomID).Scan(&pos, &spos)
 	return
 }
+
+func (s *outputRoomEventsTopologyStatements) PurgeEventsTopology(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeEventsTopologyStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/peeks_table.go

@@ -65,6 +65,9 @@ const selectPeekingDevicesSQL = "" +
 const selectMaxPeekIDSQL = "" +
 	"SELECT MAX(id) FROM syncapi_peeks"
 
+const purgePeeksSQL = "" +
+	"DELETE FROM syncapi_peeks WHERE room_id = $1"
+
 type peekStatements struct {
 	db                       *sql.DB
 	insertPeekStmt           *sql.Stmt
@@ -73,6 +76,7 @@ type peekStatements struct {
 	selectPeeksInRangeStmt   *sql.Stmt
 	selectPeekingDevicesStmt *sql.Stmt
 	selectMaxPeekIDStmt      *sql.Stmt
+	purgePeeksStmt           *sql.Stmt
 }
 
 func NewPostgresPeeksTable(db *sql.DB) (tables.Peeks, error) {
@@ -101,6 +105,9 @@ func NewPostgresPeeksTable(db *sql.DB) (tables.Peeks, error) {
 	if s.selectMaxPeekIDStmt, err = db.Prepare(selectMaxPeekIDSQL); err != nil {
 		return nil, err
 	}
+	if s.purgePeeksStmt, err = db.Prepare(purgePeeksSQL); err != nil {
+		return nil, err
+	}
 	return s, nil
 }
 
@@ -184,3 +191,10 @@ func (s *peekStatements) SelectMaxPeekID(
 	}
 	return
 }
+
+func (s *peekStatements) PurgePeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgePeeksStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/postgres/receipt_table.go

@@ -62,11 +62,15 @@ const selectRoomReceipts = "" +
 const selectMaxReceiptIDSQL = "" +
 	"SELECT MAX(id) FROM syncapi_receipts"
 
+const purgeReceiptsSQL = "" +
+	"DELETE FROM syncapi_receipts WHERE room_id = $1"
+
 type receiptStatements struct {
 	db                 *sql.DB
 	upsertReceipt      *sql.Stmt
 	selectRoomReceipts *sql.Stmt
 	selectMaxReceiptID *sql.Stmt
+	purgeReceiptsStmt  *sql.Stmt
 }
 
 func NewPostgresReceiptsTable(db *sql.DB) (tables.Receipts, error) {
@@ -95,6 +99,9 @@ func NewPostgresReceiptsTable(db *sql.DB) (tables.Receipts, error) {
 	if r.selectMaxReceiptID, err = db.Prepare(selectMaxReceiptIDSQL); err != nil {
 		return nil, fmt.Errorf("unable to prepare selectRoomReceipts statement: %w", err)
 	}
+	if r.purgeReceiptsStmt, err = db.Prepare(purgeReceiptsSQL); err != nil {
+		return nil, fmt.Errorf("unable to prepare purgeReceiptsStmt statement: %w", err)
+	}
 	return r, nil
 }
 
@@ -138,3 +145,10 @@ func (s *receiptStatements) SelectMaxReceiptID(
 	}
 	return
 }
+
+func (s *receiptStatements) PurgeReceipts(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeReceiptsStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/shared/syncserver.go

@@ -1086,3 +1086,36 @@ func (d *Database) MaxStreamPositionForPresence(ctx context.Context) (types.Stre
 func (d *Database) SelectMembershipForUser(ctx context.Context, roomID, userID string, pos int64) (membership string, topologicalPos int, err error) {
 	return d.Memberships.SelectMembershipForUser(ctx, nil, roomID, userID, pos)
 }
+
+func (d *Database) PurgeRoom(ctx context.Context, roomID string) error {
+	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+		if err := d.BackwardExtremities.PurgeBackwardExtremities(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge backward extremities: %w", err)
+		}
+		if err := d.CurrentRoomState.DeleteRoomStateForRoom(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge current room state: %w", err)
+		}
+		if err := d.Invites.PurgeInvites(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge invites: %w", err)
+		}
+		if err := d.Memberships.PurgeMemberships(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge memberships: %w", err)
+		}
+		if err := d.NotificationData.PurgeNotificationData(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge notification data: %w", err)
+		}
+		if err := d.OutputEvents.PurgeEvents(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge events: %w", err)
+		}
+		if err := d.Topology.PurgeEventsTopology(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge events topology: %w", err)
+		}
+		if err := d.Peeks.PurgePeeks(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge peeks: %w", err)
+		}
+		if err := d.Receipts.PurgeReceipts(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("failed to purge receipts: %w", err)
+		}
+		return nil
+	})
+}

syncapi/storage/sqlite3/backwards_extremities_table.go

@@ -17,6 +17,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
@@ -109,3 +110,9 @@ func (s *backwardExtremitiesStatements) DeleteBackwardExtremity(
 	_, err = sqlutil.TxStmt(txn, s.deleteBackwardExtremityStmt).ExecContext(ctx, roomID, knownEventID)
 	return err
 }
+
+func (s *backwardExtremitiesStatements) PurgeBackwardExtremities(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/invites_table.go

@@ -19,6 +19,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
@@ -183,3 +184,9 @@ func (s *inviteEventsStatements) SelectMaxInviteID(
 	}
 	return
 }
+
+func (s *inviteEventsStatements) PurgeInvites(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/memberships_table.go

@@ -170,3 +170,9 @@ func (s *membershipsStatements) SelectMembershipForUser(
 	}
 	return membership, topologyPos, nil
 }
+
+func (s *membershipsStatements) PurgeMemberships(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/notification_data_table.go

@@ -17,6 +17,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/eventutil"
@@ -112,3 +113,9 @@ func (r *notificationDataStatements) SelectMaxID(ctx context.Context, txn *sql.T
 	err := sqlutil.TxStmt(txn, r.selectMaxID).QueryRowContext(ctx).Scan(&id)
 	return id, err
 }
+
+func (s *notificationDataStatements) PurgeNotificationData(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/output_room_events_table.go

@@ -628,3 +628,9 @@ func unmarshalStateIDs(addIDsJSON, delIDsJSON string) (addIDs []string, delIDs [
 	}
 	return
 }
+
+func (s *outputRoomEventsStatements) PurgeEvents(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/output_room_events_topology_table.go

@@ -17,6 +17,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/syncapi/storage/tables"
@@ -190,3 +191,9 @@ func (s *outputRoomEventsTopologyStatements) SelectMaxPositionInTopology(
 	err = stmt.QueryRowContext(ctx, roomID).Scan(&pos, &spos)
 	return
 }
+
+func (s *outputRoomEventsTopologyStatements) PurgeEventsTopology(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/peeks_table.go

@@ -17,6 +17,7 @@ package sqlite3
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	"time"
 
 	"github.com/matrix-org/dendrite/internal"
@@ -204,3 +205,9 @@ func (s *peekStatements) SelectMaxPeekID(
 	}
 	return
 }
+
+func (s *peekStatements) PurgePeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/sqlite3/receipt_table.go

@@ -148,3 +148,9 @@ func (s *receiptStatements) SelectMaxReceiptID(
 	}
 	return
 }
+
+func (s *receiptStatements) PurgeReceipts(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	return fmt.Errorf("not implemented on SQLite")
+}

syncapi/storage/tables/interface.go

@@ -39,6 +39,7 @@ type Invites interface {
 	// for the room.
 	SelectInviteEventsInRange(ctx context.Context, txn *sql.Tx, targetUserID string, r types.Range) (invites map[string]*gomatrixserverlib.HeaderedEvent, retired map[string]*gomatrixserverlib.HeaderedEvent, err error)
 	SelectMaxInviteID(ctx context.Context, txn *sql.Tx) (id int64, err error)
+	PurgeInvites(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type Peeks interface {
@@ -48,6 +49,7 @@ type Peeks interface {
 	SelectPeeksInRange(ctxt context.Context, txn *sql.Tx, userID, deviceID string, r types.Range) (peeks []types.Peek, err error)
 	SelectPeekingDevices(ctxt context.Context) (peekingDevices map[string][]types.PeekingDevice, err error)
 	SelectMaxPeekID(ctx context.Context, txn *sql.Tx) (id int64, err error)
+	PurgePeeks(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type Events interface {
@@ -75,6 +77,8 @@ type Events interface {
 	SelectContextEvent(ctx context.Context, txn *sql.Tx, roomID, eventID string) (int, gomatrixserverlib.HeaderedEvent, error)
 	SelectContextBeforeEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) ([]*gomatrixserverlib.HeaderedEvent, error)
 	SelectContextAfterEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) (int, []*gomatrixserverlib.HeaderedEvent, error)
+
+	PurgeEvents(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 // Topology keeps track of the depths and stream positions for all events.
@@ -94,6 +98,7 @@ type Topology interface {
 	SelectMaxPositionInTopology(ctx context.Context, txn *sql.Tx, roomID string) (depth types.StreamPosition, spos types.StreamPosition, err error)
 	// SelectStreamToTopologicalPosition converts a stream position to a topological position by finding the nearest topological position in the room.
 	SelectStreamToTopologicalPosition(ctx context.Context, txn *sql.Tx, roomID string, streamPos types.StreamPosition, forward bool) (topoPos types.StreamPosition, err error)
+	PurgeEventsTopology(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type CurrentRoomState interface {
@@ -144,6 +149,7 @@ type BackwardsExtremities interface {
 	SelectBackwardExtremitiesForRoom(ctx context.Context, roomID string) (bwExtrems map[string][]string, err error)
 	// DeleteBackwardExtremity removes a backwards extremity for a room, if one existed.
 	DeleteBackwardExtremity(ctx context.Context, txn *sql.Tx, roomID, knownEventID string) (err error)
+	PurgeBackwardExtremities(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 // SendToDevice tracks send-to-device messages which are sent to individual
@@ -179,6 +185,7 @@ type Receipts interface {
 	UpsertReceipt(ctx context.Context, txn *sql.Tx, roomId, receiptType, userId, eventId string, timestamp gomatrixserverlib.Timestamp) (pos types.StreamPosition, err error)
 	SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []types.OutputReceiptEvent, error)
 	SelectMaxReceiptID(ctx context.Context, txn *sql.Tx) (id int64, err error)
+	PurgeReceipts(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type Memberships interface {
@@ -186,12 +193,14 @@ type Memberships interface {
 	SelectMembershipCount(ctx context.Context, txn *sql.Tx, roomID, membership string, pos types.StreamPosition) (count int, err error)
 	SelectHeroes(ctx context.Context, txn *sql.Tx, roomID, userID string, memberships []string) (heroes []string, err error)
 	SelectMembershipForUser(ctx context.Context, txn *sql.Tx, roomID, userID string, pos int64) (membership string, topologicalPos int, err error)
+	PurgeMemberships(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type NotificationData interface {
 	UpsertRoomUnreadCounts(ctx context.Context, txn *sql.Tx, userID, roomID string, notificationCount, highlightCount int) (types.StreamPosition, error)
 	SelectUserUnreadCounts(ctx context.Context, txn *sql.Tx, userID string, fromExcl, toIncl types.StreamPosition) (map[string]*eventutil.NotificationData, error)
 	SelectMaxID(ctx context.Context, txn *sql.Tx) (int64, error)
+	PurgeNotificationData(ctx context.Context, txn *sql.Tx, roomID string) error
 }
 
 type Ignores interface {