Add Range (#1037)

* Add Range

* Use Range

syncapi/storage/interface.go

@@ -64,7 +64,7 @@ type Database interface {
 	// Returns a map following the format data[roomID] = []dataTypes
 	// If no data is retrieved, returns an empty map
 	// If there was an issue with the retrieval, returns an error
-	GetAccountDataInRange(ctx context.Context, userID string, oldPos, newPos types.StreamPosition, accountDataFilterPart *gomatrixserverlib.EventFilter) (map[string][]string, error)
+	GetAccountDataInRange(ctx context.Context, userID string, r types.Range, accountDataFilterPart *gomatrixserverlib.EventFilter) (map[string][]string, error)
 	// UpsertAccountData keeps track of new or updated account data, by saving the type
 	// of the new/updated data, and the user ID and room ID the data is related to (empty)
 	// room ID means the data isn't specific to any room)

syncapi/storage/postgres/account_data_table.go

@@ -100,19 +100,12 @@ func (s *accountDataStatements) InsertAccountData(
 func (s *accountDataStatements) SelectAccountDataInRange(
 	ctx context.Context,
 	userID string,
-	oldPos, newPos types.StreamPosition,
+	r types.Range,
 	accountDataEventFilter *gomatrixserverlib.EventFilter,
 ) (data map[string][]string, err error) {
 	data = make(map[string][]string)
 
-	// If both positions are the same, it means that the data was saved after the
+	rows, err := s.selectAccountDataInRangeStmt.QueryContext(ctx, userID, r.Low(), r.High(),
-	// latest room event. In that case, we need to decrement the old position as
-	// it would prevent the SQL request from returning anything.
-	if oldPos == newPos {
-		oldPos--
-	}
-
-	rows, err := s.selectAccountDataInRangeStmt.QueryContext(ctx, userID, oldPos, newPos,
 		pq.StringArray(filterConvertTypeWildcardToSQL(accountDataEventFilter.Types)),
 		pq.StringArray(filterConvertTypeWildcardToSQL(accountDataEventFilter.NotTypes)),
 		accountDataEventFilter.Limit,

syncapi/storage/postgres/invites_table.go

@@ -117,10 +117,10 @@ func (s *inviteEventsStatements) DeleteInviteEvent(
 // selectInviteEventsInRange returns a map of room ID to invite event for the
 // active invites for the target user ID in the supplied range.
 func (s *inviteEventsStatements) SelectInviteEventsInRange(
-	ctx context.Context, txn *sql.Tx, targetUserID string, startPos, endPos types.StreamPosition,
+	ctx context.Context, txn *sql.Tx, targetUserID string, r types.Range,
 ) (map[string]gomatrixserverlib.HeaderedEvent, error) {
 	stmt := common.TxStmt(txn, s.selectInviteEventsInRangeStmt)
-	rows, err := stmt.QueryContext(ctx, targetUserID, startPos, endPos)
+	rows, err := stmt.QueryContext(ctx, targetUserID, r.Low(), r.High())
 	if err != nil {
 		return nil, err
 	}

syncapi/storage/postgres/output_room_events_table.go

@@ -155,13 +155,13 @@ func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
 // Results are bucketed based on the room ID. If the same state is overwritten multiple times between the
 // two positions, only the most recent state is returned.
 func (s *outputRoomEventsStatements) SelectStateInRange(
-	ctx context.Context, txn *sql.Tx, oldPos, newPos types.StreamPosition,
+	ctx context.Context, txn *sql.Tx, r types.Range,
 	stateFilter *gomatrixserverlib.StateFilter,
 ) (map[string]map[string]bool, map[string]types.StreamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectStateInRangeStmt)
 
 	rows, err := stmt.QueryContext(
-		ctx, oldPos, newPos,
+		ctx, r.Low(), r.High(),
 		pq.StringArray(stateFilter.Senders),
 		pq.StringArray(stateFilter.NotSenders),
 		pq.StringArray(filterConvertTypeWildcardToSQL(stateFilter.Types)),
@@ -198,8 +198,8 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 		// since it'll just mark the event as not being needed.
 		if len(addIDs) < len(delIDs) {
 			log.WithFields(log.Fields{
-				"since":   oldPos,
+				"since":   r.From,
-				"current": newPos,
+				"current": r.To,
 				"adds":    addIDs,
 				"dels":    delIDs,
 			}).Warn("StateBetween: ignoring deleted state")
@@ -298,7 +298,7 @@ func (s *outputRoomEventsStatements) InsertEvent(
 // from sync.
 func (s *outputRoomEventsStatements) SelectRecentEvents(
 	ctx context.Context, txn *sql.Tx,
-	roomID string, fromPos, toPos types.StreamPosition, limit int,
+	roomID string, r types.Range, limit int,
 	chronologicalOrder bool, onlySyncEvents bool,
 ) ([]types.StreamEvent, error) {
 	var stmt *sql.Stmt
@@ -307,7 +307,7 @@ func (s *outputRoomEventsStatements) SelectRecentEvents(
 	} else {
 		stmt = common.TxStmt(txn, s.selectRecentEventsStmt)
 	}
-	rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, limit)
+	rows, err := stmt.QueryContext(ctx, roomID, r.Low(), r.High(), limit)
 	if err != nil {
 		return nil, err
 	}
@@ -331,10 +331,10 @@ func (s *outputRoomEventsStatements) SelectRecentEvents(
 // from a given position, up to a maximum of 'limit'.
 func (s *outputRoomEventsStatements) SelectEarlyEvents(
 	ctx context.Context, txn *sql.Tx,
-	roomID string, fromPos, toPos types.StreamPosition, limit int,
+	roomID string, r types.Range, limit int,
 ) ([]types.StreamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectEarlyEventsStmt)
-	rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, limit)
+	rows, err := stmt.QueryContext(ctx, roomID, r.Low(), r.High(), limit)
 	if err != nil {
 		return nil, err
 	}

syncapi/storage/shared/syncserver.go

@@ -54,17 +54,22 @@ func (d *Database) GetEventsInStreamingRange(
 	roomID string, limit int,
 	backwardOrdering bool,
 ) (events []types.StreamEvent, err error) {
+	r := types.Range{
+		From:      from.PDUPosition(),
+		To:        to.PDUPosition(),
+		Backwards: backwardOrdering,
+	}
 	if backwardOrdering {
 		// When using backward ordering, we want the most recent events first.
 		if events, err = d.OutputEvents.SelectRecentEvents(
-			ctx, nil, roomID, to.PDUPosition(), from.PDUPosition(), limit, false, false,
+			ctx, nil, roomID, r, limit, false, false,
 		); err != nil {
 			return
 		}
 	} else {
 		// When using forward ordering, we want the least recent events first.
 		if events, err = d.OutputEvents.SelectEarlyEvents(
-			ctx, nil, roomID, from.PDUPosition(), to.PDUPosition(), limit,
+			ctx, nil, roomID, r, limit,
 		); err != nil {
 			return
 		}
@@ -167,10 +172,10 @@ func (d *Database) RetireInviteEvent(
 // If no data is retrieved, returns an empty map
 // If there was an issue with the retrieval, returns an error
 func (d *Database) GetAccountDataInRange(
-	ctx context.Context, userID string, oldPos, newPos types.StreamPosition,
+	ctx context.Context, userID string, r types.Range,
 	accountDataFilterPart *gomatrixserverlib.EventFilter,
 ) (map[string][]string, error) {
-	return d.AccountData.SelectAccountDataInRange(ctx, userID, oldPos, newPos, accountDataFilterPart)
+	return d.AccountData.SelectAccountDataInRange(ctx, userID, r, accountDataFilterPart)
 }
 
 // UpsertAccountData keeps track of new or updated account data, by saving the type
@@ -417,7 +422,7 @@ func (d *Database) syncPositionTx(
 func (d *Database) addPDUDeltaToResponse(
 	ctx context.Context,
 	device authtypes.Device,
-	fromPos, toPos types.StreamPosition,
+	r types.Range,
 	numRecentEventsPerRoom int,
 	wantFullState bool,
 	res *types.Response,
@@ -443,11 +448,11 @@ func (d *Database) addPDUDeltaToResponse(
 	var deltas []stateDelta
 	if !wantFullState {
 		deltas, joinedRoomIDs, err = d.getStateDeltas(
-			ctx, &device, txn, fromPos, toPos, device.UserID, &stateFilter,
+			ctx, &device, txn, r, device.UserID, &stateFilter,
 		)
 	} else {
 		deltas, joinedRoomIDs, err = d.getStateDeltasForFullStateSync(
-			ctx, &device, txn, fromPos, toPos, device.UserID, &stateFilter,
+			ctx, &device, txn, r, device.UserID, &stateFilter,
 		)
 	}
 	if err != nil {
@@ -455,14 +460,14 @@ func (d *Database) addPDUDeltaToResponse(
 	}
 
 	for _, delta := range deltas {
-		err = d.addRoomDeltaToResponse(ctx, &device, txn, fromPos, toPos, delta, numRecentEventsPerRoom, res)
+		err = d.addRoomDeltaToResponse(ctx, &device, txn, r, delta, numRecentEventsPerRoom, res)
 		if err != nil {
 			return nil, err
 		}
 	}
 
 	// TODO: This should be done in getStateDeltas
-	if err = d.addInvitesToResponse(ctx, txn, device.UserID, fromPos, toPos, res); err != nil {
+	if err = d.addInvitesToResponse(ctx, txn, device.UserID, r, res); err != nil {
 		return nil, err
 	}
 
@@ -534,8 +539,12 @@ func (d *Database) IncrementalSync(
 	var joinedRoomIDs []string
 	var err error
 	if fromPos.PDUPosition() != toPos.PDUPosition() || wantFullState {
+		r := types.Range{
+			From: fromPos.PDUPosition(),
+			To:   toPos.PDUPosition(),
+		}
 		joinedRoomIDs, err = d.addPDUDeltaToResponse(
-			ctx, device, fromPos.PDUPosition(), toPos.PDUPosition(), numRecentEventsPerRoom, wantFullState, res,
+			ctx, device, r, numRecentEventsPerRoom, wantFullState, res,
 		)
 	} else {
 		joinedRoomIDs, err = d.CurrentRoomState.SelectRoomIDsWithMembership(
@@ -589,6 +598,10 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 	if err != nil {
 		return
 	}
+	r := types.Range{
+		From: 0,
+		To:   toPos.PDUPosition(),
+	}
 
 	res = types.NewResponse(toPos)
 
@@ -611,8 +624,7 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 		//       See: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L316
 		var recentStreamEvents []types.StreamEvent
 		recentStreamEvents, err = d.OutputEvents.SelectRecentEvents(
-			ctx, txn, roomID, types.StreamPosition(0), toPos.PDUPosition(),
+			ctx, txn, roomID, r, numRecentEventsPerRoom, true, true,
-			numRecentEventsPerRoom, true, true,
 		)
 		if err != nil {
 			return
@@ -644,7 +656,7 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 		res.Rooms.Join[roomID] = *jr
 	}
 
-	if err = d.addInvitesToResponse(ctx, txn, userID, 0, toPos.PDUPosition(), res); err != nil {
+	if err = d.addInvitesToResponse(ctx, txn, userID, r, res); err != nil {
 		return
 	}
 
@@ -686,11 +698,11 @@ var txReadOnlySnapshot = sql.TxOptions{
 func (d *Database) addInvitesToResponse(
 	ctx context.Context, txn *sql.Tx,
 	userID string,
-	fromPos, toPos types.StreamPosition,
+	r types.Range,
 	res *types.Response,
 ) error {
 	invites, err := d.Invites.SelectInviteEventsInRange(
-		ctx, txn, userID, fromPos, toPos,
+		ctx, txn, userID, r,
 	)
 	if err != nil {
 		return err
@@ -726,12 +738,11 @@ func (d *Database) addRoomDeltaToResponse(
 	ctx context.Context,
 	device *authtypes.Device,
 	txn *sql.Tx,
-	fromPos, toPos types.StreamPosition,
+	r types.Range,
 	delta stateDelta,
 	numRecentEventsPerRoom int,
 	res *types.Response,
 ) error {
-	endPos := toPos
 	if delta.membershipPos > 0 && delta.membership == gomatrixserverlib.Leave {
 		// make sure we don't leak recent events after the leave event.
 		// TODO: History visibility makes this somewhat complex to handle correctly. For example:
@@ -739,10 +750,10 @@ func (d *Database) addRoomDeltaToResponse(
 		// TODO: This will fail on join -> leave -> sensitive msg -> join -> leave
 		//       in a single /sync request
 		// This is all "okay" assuming history_visibility == "shared" which it is by default.
-		endPos = delta.membershipPos
+		r.To = delta.membershipPos
 	}
 	recentStreamEvents, err := d.OutputEvents.SelectRecentEvents(
-		ctx, txn, delta.roomID, types.StreamPosition(fromPos), types.StreamPosition(endPos),
+		ctx, txn, delta.roomID, r,
 		numRecentEventsPerRoom, true, true,
 	)
 	if err != nil {
@@ -872,7 +883,7 @@ func (d *Database) fetchMissingStateEvents(
 // A list of joined room IDs is also returned in case the caller needs it.
 func (d *Database) getStateDeltas(
 	ctx context.Context, device *authtypes.Device, txn *sql.Tx,
-	fromPos, toPos types.StreamPosition, userID string,
+	r types.Range, userID string,
 	stateFilter *gomatrixserverlib.StateFilter,
 ) ([]stateDelta, []string, error) {
 	// Implement membership change algorithm: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L821
@@ -886,7 +897,7 @@ func (d *Database) getStateDeltas(
 	var deltas []stateDelta
 
 	// get all the state events ever between these two positions
-	stateNeeded, eventMap, err := d.OutputEvents.SelectStateInRange(ctx, txn, fromPos, toPos, stateFilter)
+	stateNeeded, eventMap, err := d.OutputEvents.SelectStateInRange(ctx, txn, r, stateFilter)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -947,7 +958,7 @@ func (d *Database) getStateDeltas(
 // updates for other rooms.
 func (d *Database) getStateDeltasForFullStateSync(
 	ctx context.Context, device *authtypes.Device, txn *sql.Tx,
-	fromPos, toPos types.StreamPosition, userID string,
+	r types.Range, userID string,
 	stateFilter *gomatrixserverlib.StateFilter,
 ) ([]stateDelta, []string, error) {
 	joinedRoomIDs, err := d.CurrentRoomState.SelectRoomIDsWithMembership(ctx, txn, userID, gomatrixserverlib.Join)
@@ -972,7 +983,7 @@ func (d *Database) getStateDeltasForFullStateSync(
 	}
 
 	// Get all the state events ever between these two positions
-	stateNeeded, eventMap, err := d.OutputEvents.SelectStateInRange(ctx, txn, fromPos, toPos, stateFilter)
+	stateNeeded, eventMap, err := d.OutputEvents.SelectStateInRange(ctx, txn, r, stateFilter)
 	if err != nil {
 		return nil, nil, err
 	}

syncapi/storage/sqlite3/account_data_table.go

@@ -91,19 +91,12 @@ func (s *accountDataStatements) InsertAccountData(
 func (s *accountDataStatements) SelectAccountDataInRange(
 	ctx context.Context,
 	userID string,
-	oldPos, newPos types.StreamPosition,
+	r types.Range,
 	accountDataFilterPart *gomatrixserverlib.EventFilter,
 ) (data map[string][]string, err error) {
 	data = make(map[string][]string)
 
-	// If both positions are the same, it means that the data was saved after the
+	rows, err := s.selectAccountDataInRangeStmt.QueryContext(ctx, userID, r.Low(), r.High())
-	// latest room event. In that case, we need to decrement the old position as
-	// it would prevent the SQL request from returning anything.
-	if oldPos == newPos {
-		oldPos--
-	}
-
-	rows, err := s.selectAccountDataInRangeStmt.QueryContext(ctx, userID, oldPos, newPos)
 	if err != nil {
 		return
 	}

syncapi/storage/sqlite3/invites_table.go

@@ -121,10 +121,10 @@ func (s *inviteEventsStatements) DeleteInviteEvent(
 // selectInviteEventsInRange returns a map of room ID to invite event for the
 // active invites for the target user ID in the supplied range.
 func (s *inviteEventsStatements) SelectInviteEventsInRange(
-	ctx context.Context, txn *sql.Tx, targetUserID string, startPos, endPos types.StreamPosition,
+	ctx context.Context, txn *sql.Tx, targetUserID string, r types.Range,
 ) (map[string]gomatrixserverlib.HeaderedEvent, error) {
 	stmt := common.TxStmt(txn, s.selectInviteEventsInRangeStmt)
-	rows, err := stmt.QueryContext(ctx, targetUserID, startPos, endPos)
+	rows, err := stmt.QueryContext(ctx, targetUserID, r.Low(), r.High())
 	if err != nil {
 		return nil, err
 	}

syncapi/storage/sqlite3/output_room_events_table.go

@@ -146,13 +146,13 @@ func NewSqliteEventsTable(db *sql.DB, streamID *streamIDStatements) (tables.Even
 // Results are bucketed based on the room ID. If the same state is overwritten multiple times between the
 // two positions, only the most recent state is returned.
 func (s *outputRoomEventsStatements) SelectStateInRange(
-	ctx context.Context, txn *sql.Tx, oldPos, newPos types.StreamPosition,
+	ctx context.Context, txn *sql.Tx, r types.Range,
 	stateFilterPart *gomatrixserverlib.StateFilter,
 ) (map[string]map[string]bool, map[string]types.StreamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectStateInRangeStmt)
 
 	rows, err := stmt.QueryContext(
-		ctx, oldPos, newPos,
+		ctx, r.Low(), r.High(),
 		/*pq.StringArray(stateFilterPart.Senders),
 		pq.StringArray(stateFilterPart.NotSenders),
 		pq.StringArray(filterConvertTypeWildcardToSQL(stateFilterPart.Types)),
@@ -195,8 +195,8 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 		// since it'll just mark the event as not being needed.
 		if len(addIDs) < len(delIDs) {
 			log.WithFields(log.Fields{
-				"since":   oldPos,
+				"since":   r.From,
-				"current": newPos,
+				"current": r.To,
 				"adds":    addIDsJSON,
 				"dels":    delIDsJSON,
 			}).Warn("StateBetween: ignoring deleted state")
@@ -308,7 +308,7 @@ func (s *outputRoomEventsStatements) InsertEvent(
 
 func (s *outputRoomEventsStatements) SelectRecentEvents(
 	ctx context.Context, txn *sql.Tx,
-	roomID string, fromPos, toPos types.StreamPosition, limit int,
+	roomID string, r types.Range, limit int,
 	chronologicalOrder bool, onlySyncEvents bool,
 ) ([]types.StreamEvent, error) {
 	var stmt *sql.Stmt
@@ -318,7 +318,7 @@ func (s *outputRoomEventsStatements) SelectRecentEvents(
 		stmt = common.TxStmt(txn, s.selectRecentEventsStmt)
 	}
 
-	rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, limit)
+	rows, err := stmt.QueryContext(ctx, roomID, r.Low(), r.High(), limit)
 	if err != nil {
 		return nil, err
 	}
@@ -340,10 +340,10 @@ func (s *outputRoomEventsStatements) SelectRecentEvents(
 
 func (s *outputRoomEventsStatements) SelectEarlyEvents(
 	ctx context.Context, txn *sql.Tx,
-	roomID string, fromPos, toPos types.StreamPosition, limit int,
+	roomID string, r types.Range, limit int,
 ) ([]types.StreamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectEarlyEventsStmt)
-	rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, limit)
+	rows, err := stmt.QueryContext(ctx, roomID, r.Low(), r.High(), limit)
 	if err != nil {
 		return nil, err
 	}

syncapi/storage/tables/interface.go

@@ -11,29 +11,29 @@ import (
 
 type AccountData interface {
 	InsertAccountData(ctx context.Context, txn *sql.Tx, userID, roomID, dataType string) (pos types.StreamPosition, err error)
-	// SelectAccountDataInRange returns a map of room ID to a list of `dataType`. The range is exclusive of `lowPos` and inclusive of `hiPos`.
+	// SelectAccountDataInRange returns a map of room ID to a list of `dataType`.
-	SelectAccountDataInRange(ctx context.Context, userID string, lowPos, hiPos types.StreamPosition, accountDataEventFilter *gomatrixserverlib.EventFilter) (data map[string][]string, err error)
+	SelectAccountDataInRange(ctx context.Context, userID string, r types.Range, accountDataEventFilter *gomatrixserverlib.EventFilter) (data map[string][]string, err error)
 	SelectMaxAccountDataID(ctx context.Context, txn *sql.Tx) (id int64, err error)
 }
 
 type Invites interface {
 	InsertInviteEvent(ctx context.Context, txn *sql.Tx, inviteEvent gomatrixserverlib.HeaderedEvent) (streamPos types.StreamPosition, err error)
 	DeleteInviteEvent(ctx context.Context, inviteEventID string) error
-	// SelectInviteEventsInRange returns a map of room ID to invite events. The range is exclusive of `startPos` and inclusive of `endPos`.
+	// SelectInviteEventsInRange returns a map of room ID to invite events.
-	SelectInviteEventsInRange(ctx context.Context, txn *sql.Tx, targetUserID string, startPos, endPos types.StreamPosition) (map[string]gomatrixserverlib.HeaderedEvent, error)
+	SelectInviteEventsInRange(ctx context.Context, txn *sql.Tx, targetUserID string, r types.Range) (map[string]gomatrixserverlib.HeaderedEvent, error)
 	SelectMaxInviteID(ctx context.Context, txn *sql.Tx) (id int64, err error)
 }
 
 type Events interface {
-	SelectStateInRange(ctx context.Context, txn *sql.Tx, oldPos, newPos types.StreamPosition, stateFilter *gomatrixserverlib.StateFilter) (map[string]map[string]bool, map[string]types.StreamEvent, error)
+	SelectStateInRange(ctx context.Context, txn *sql.Tx, r types.Range, stateFilter *gomatrixserverlib.StateFilter) (map[string]map[string]bool, map[string]types.StreamEvent, error)
 	SelectMaxEventID(ctx context.Context, txn *sql.Tx) (id int64, err error)
 	InsertEvent(ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent, addState, removeState []string, transactionID *api.TransactionID, excludeFromSync bool) (streamPos types.StreamPosition, err error)
-	// SelectRecentEvents returns events between the two stream positions: exclusive of `fromPos` and inclusive of `toPos`.
+	// SelectRecentEvents returns events between the two stream positions: exclusive of low and inclusive of high.
 	// If onlySyncEvents has a value of true, only returns the events that aren't marked as to exclude from sync.
 	// Returns up to `limit` events.
-	SelectRecentEvents(ctx context.Context, txn *sql.Tx, roomID string, fromPos, toPos types.StreamPosition, limit int, chronologicalOrder bool, onlySyncEvents bool) ([]types.StreamEvent, error)
+	SelectRecentEvents(ctx context.Context, txn *sql.Tx, roomID string, r types.Range, limit int, chronologicalOrder bool, onlySyncEvents bool) ([]types.StreamEvent, error)
-	// SelectEarlyEvents returns the earliest events in the given room, exclusive of `fromPos` and inclusive of `toPos`.
+	// SelectEarlyEvents returns the earliest events in the given room.
-	SelectEarlyEvents(ctx context.Context, txn *sql.Tx, roomID string, fromPos, toPos types.StreamPosition, limit int) ([]types.StreamEvent, error)
+	SelectEarlyEvents(ctx context.Context, txn *sql.Tx, roomID string, r types.Range, limit int) ([]types.StreamEvent, error)
 	SelectEvents(ctx context.Context, txn *sql.Tx, eventIDs []string) ([]types.StreamEvent, error)
 }
 

syncapi/sync/requestpool.go

@@ -184,11 +184,20 @@ func (rp *RequestPool) appendAccountData(
 		return data, nil
 	}
 
+	r := types.Range{
+		From: req.since.PDUPosition(),
+		To:   currentPos,
+	}
+	// If both positions are the same, it means that the data was saved after the
+	// latest room event. In that case, we need to decrement the old position as
+	// results are exclusive of Low.
+	if r.Low() == r.High() {
+		r.From--
+	}
+
 	// Sync is not initial, get all account data since the latest sync
 	dataTypes, err := rp.db.GetAccountDataInRange(
-		req.ctx, userID,
+		req.ctx, userID, r, accountDataFilter,
-		types.StreamPosition(req.since.PDUPosition()), types.StreamPosition(currentPos),
-		accountDataFilter,
 	)
 	if err != nil {
 		return nil, err

syncapi/types/types.go

@@ -47,6 +47,34 @@ type StreamEvent struct {
 	ExcludeFromSync bool
 }
 
+// Range represents a range between two stream positions.
+type Range struct {
+	// From is the position the client has already received.
+	From StreamPosition
+	// To is the position the client is going towards.
+	To StreamPosition
+	// True if the client is going backwards
+	Backwards bool
+}
+
+// Low returns the low number of the range.
+// This represents the position the client already has and hence is exclusive.
+func (r *Range) Low() StreamPosition {
+	if !r.Backwards {
+		return r.From
+	}
+	return r.To
+}
+
+// High returns the high number of the range
+// This represents the position the client is going towards and hence is inclusive.
+func (r *Range) High() StreamPosition {
+	if !r.Backwards {
+		return r.To
+	}
+	return r.From
+}
+
 // SyncTokenType represents the type of a sync token.
 // It can be either "s" (representing a position in the whole stream of events)
 // or "t" (representing a position in a room's topology/depth).