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Cleanup syncapi topology logic (#1035)

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* Cleanup syncapi topology logic

* Variable renaming

* comments
This commit is contained in:
Kegsay 2020-05-14 17:30:16 +01:00 committed by GitHub
parent 3cb04e8004
commit 7ca230e931
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GPG key ID: 4AEE18F83AFDEB23
9 changed files with 67 additions and 154 deletions
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16
syncapi/routing/messages.go
View file

@ -245,24 +245,20 @@ func (r *messagesReq) retrieveEvents() (
// change the way topological positions are defined (as depth isn't the most
// reliable way to define it), it would be easier and less troublesome to
// only have to change it in one place, i.e. the database.
startPos, startStreamPos, err := r.db.EventPositionInTopology(
start, err = r.db.EventPositionInTopology(
r.ctx, events[0].EventID(),
)
if err != nil {
err = fmt.Errorf("EventPositionInTopology: for start event %s: %w", events[0].EventID(), err)
return
}
endPos, endStreamPos, err := r.db.EventPositionInTopology(
end, err = r.db.EventPositionInTopology(
r.ctx, events[len(events)-1].EventID(),
)
if err != nil {
err = fmt.Errorf("EventPositionInTopology: for end event %s: %w", events[len(events)-1].EventID(), err)
return
}
// Generate pagination tokens to send to the client using the positions
// retrieved previously.
start = types.NewTopologyToken(startPos, startStreamPos)
end = types.NewTopologyToken(endPos, endStreamPos)
if r.backwardOrdering {
// A stream/topological position is a cursor located between two events.
@ -431,14 +427,10 @@ func setToDefault(
) (to types.TopologyToken, err error) {
if backwardOrdering {
// go 1 earlier than the first event so we correctly fetch the earliest event
// this is because Database.GetEventsInTopologicalRange is exclusive of the lower-bound.
to = types.NewTopologyToken(0, 0)
} else {
var depth, stream types.StreamPosition
depth, stream, err = db.MaxTopologicalPosition(ctx, roomID)
if err != nil {
return
}
to = types.NewTopologyToken(depth, stream)
to, err = db.MaxTopologicalPosition(ctx, roomID)
}
return

7
syncapi/storage/interface.go
View file

@ -93,15 +93,12 @@ type Database interface {
// GetEventsInTopologicalRange retrieves all of the events on a given ordering using the given extremities and limit.
GetEventsInTopologicalRange(ctx context.Context, from, to *types.TopologyToken, roomID string, limit int, backwardOrdering bool) (events []types.StreamEvent, err error)
// EventPositionInTopology returns the depth and stream position of the given event.
EventPositionInTopology(ctx context.Context, eventID string) (depth types.StreamPosition, stream types.StreamPosition, err error)
// EventsAtTopologicalPosition returns all of the events matching a given
// position in the topology of a given room.
EventsAtTopologicalPosition(ctx context.Context, roomID string, pos types.StreamPosition) ([]types.StreamEvent, error)
EventPositionInTopology(ctx context.Context, eventID string) (types.TopologyToken, error)
// BackwardExtremitiesForRoom returns the event IDs of all of the backward
// extremities we know of for a given room.
BackwardExtremitiesForRoom(ctx context.Context, roomID string) (backwardExtremities []string, err error)
// MaxTopologicalPosition returns the highest topological position for a given room.
MaxTopologicalPosition(ctx context.Context, roomID string) (depth types.StreamPosition, stream types.StreamPosition, err error)
MaxTopologicalPosition(ctx context.Context, roomID string) (types.TopologyToken, error)
// StreamEventsToEvents converts streamEvent to Event. If device is non-nil and
// matches the streamevent.transactionID device then the transaction ID gets
// added to the unsigned section of the output event.

37
syncapi/storage/postgres/output_room_events_topology_table.go
View file

@ -72,17 +72,12 @@ const selectMaxPositionInTopologySQL = "" +
"SELECT MAX(topological_position) FROM syncapi_output_room_events_topology WHERE room_id=$1" +
") ORDER BY stream_position DESC LIMIT 1"
const selectEventIDsFromPositionSQL = "" +
"SELECT event_id FROM syncapi_output_room_events_topology" +
" WHERE room_id = $1 AND topological_position = $2"
type outputRoomEventsTopologyStatements struct {
insertEventInTopologyStmt *sql.Stmt
selectEventIDsInRangeASCStmt *sql.Stmt
selectEventIDsInRangeDESCStmt *sql.Stmt
selectPositionInTopologyStmt *sql.Stmt
selectMaxPositionInTopologyStmt *sql.Stmt
selectEventIDsFromPositionStmt *sql.Stmt
}
func NewPostgresTopologyTable(db *sql.DB) (tables.Topology, error) {
@ -106,9 +101,6 @@ func NewPostgresTopologyTable(db *sql.DB) (tables.Topology, error) {
if s.selectMaxPositionInTopologyStmt, err = db.Prepare(selectMaxPositionInTopologySQL); err != nil {
return nil, err
}
if s.selectEventIDsFromPositionStmt, err = db.Prepare(selectEventIDsFromPositionSQL); err != nil {
return nil, err
}
return s, nil
}
@ -127,7 +119,7 @@ func (s *outputRoomEventsTopologyStatements) InsertEventInTopology(
// given range in a given room's topological order.
// Returns an empty slice if no events match the given range.
func (s *outputRoomEventsTopologyStatements) SelectEventIDsInRange(
ctx context.Context, txn *sql.Tx, roomID string, fromPos, toPos, toMicroPos types.StreamPosition,
ctx context.Context, txn *sql.Tx, roomID string, minDepth, maxDepth, maxStreamPos types.StreamPosition,
limit int, chronologicalOrder bool,
) (eventIDs []string, err error) {
// Decide on the selection's order according to whether chronological order
@ -140,7 +132,7 @@ func (s *outputRoomEventsTopologyStatements) SelectEventIDsInRange(
}
// Query the event IDs.
rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, toPos, toMicroPos, limit)
rows, err := stmt.QueryContext(ctx, roomID, minDepth, maxDepth, maxDepth, maxStreamPos, limit)
if err == sql.ErrNoRows {
// If no event matched the request, return an empty slice.
return []string{}, nil
@ -176,28 +168,3 @@ func (s *outputRoomEventsTopologyStatements) SelectMaxPositionInTopology(
err = s.selectMaxPositionInTopologyStmt.QueryRowContext(ctx, roomID).Scan(&pos, &spos)
return
}
// SelectEventIDsFromPosition returns the IDs of all events that have a given
// position in the topology of a given room.
func (s *outputRoomEventsTopologyStatements) SelectEventIDsFromPosition(
ctx context.Context, txn *sql.Tx, roomID string, pos types.StreamPosition,
) (eventIDs []string, err error) {
// Query the event IDs.
rows, err := s.selectEventIDsFromPositionStmt.QueryContext(ctx, roomID, pos)
if err == sql.ErrNoRows {
// If no event matched the request, return an empty slice.
return []string{}, nil
} else if err != nil {
return
}
defer common.CloseAndLogIfError(ctx, rows, "selectEventIDsFromPosition: rows.close() failed")
// Return the IDs.
var eventID string
for rows.Next() {
if err = rows.Scan(&eventID); err != nil {
return
}
eventIDs = append(eventIDs, eventID)
}
return eventIDs, rows.Err()
}

68
syncapi/storage/shared/syncserver.go
View file

@ -319,25 +319,25 @@ func (d *Database) GetEventsInTopologicalRange(
roomID string, limit int,
backwardOrdering bool,
) (events []types.StreamEvent, err error) {
// Determine the backward and forward limit, i.e. the upper and lower
// limits to the selection in the room's topology, from the direction.
var backwardLimit, forwardLimit, forwardMicroLimit types.StreamPosition
var minDepth, maxDepth, maxStreamPosForMaxDepth types.StreamPosition
if backwardOrdering {
// Backward ordering is antichronological (latest event to oldest
// one).
backwardLimit = to.Depth()
forwardLimit = from.Depth()
forwardMicroLimit = from.PDUPosition()
// Backward ordering means the 'from' token has a higher depth than the 'to' token
minDepth = to.Depth()
maxDepth = from.Depth()
// for cases where we have say 5 events with the same depth, the TopologyToken needs to
// know which of the 5 the client has seen. This is done by using the PDU position.
// Events with the same maxDepth but less than this PDU position will be returned.
maxStreamPosForMaxDepth = from.PDUPosition()
} else {
// Forward ordering is chronological (oldest event to latest one).
backwardLimit = from.Depth()
forwardLimit = to.Depth()
// Forward ordering means the 'from' token has a lower depth than the 'to' token.
minDepth = from.Depth()
maxDepth = to.Depth()
}
// Select the event IDs from the defined range.
var eIDs []string
eIDs, err = d.Topology.SelectEventIDsInRange(
ctx, nil, roomID, backwardLimit, forwardLimit, forwardMicroLimit, limit, !backwardOrdering,
ctx, nil, roomID, minDepth, maxDepth, maxStreamPosForMaxDepth, limit, !backwardOrdering,
)
if err != nil {
return
@ -350,7 +350,7 @@ func (d *Database) GetEventsInTopologicalRange(
func (d *Database) SyncPosition(ctx context.Context) (tok types.StreamingToken, err error) {
err = common.WithTransaction(d.DB, func(txn *sql.Tx) error {
pos, err := d.SyncPositionTx(ctx, txn)
pos, err := d.syncPositionTx(ctx, txn)
if err != nil {
return err
}
@ -368,29 +368,25 @@ func (d *Database) BackwardExtremitiesForRoom(
func (d *Database) MaxTopologicalPosition(
ctx context.Context, roomID string,
) (depth types.StreamPosition, stream types.StreamPosition, err error) {
return d.Topology.SelectMaxPositionInTopology(ctx, nil, roomID)
}
func (d *Database) EventsAtTopologicalPosition(
ctx context.Context, roomID string, pos types.StreamPosition,
) ([]types.StreamEvent, error) {
eIDs, err := d.Topology.SelectEventIDsFromPosition(ctx, nil, roomID, pos)
) (types.TopologyToken, error) {
depth, streamPos, err := d.Topology.SelectMaxPositionInTopology(ctx, nil, roomID)
if err != nil {
return nil, err
return types.NewTopologyToken(0, 0), err
}
return d.OutputEvents.SelectEvents(ctx, nil, eIDs)
return types.NewTopologyToken(depth, streamPos), nil
}
func (d *Database) EventPositionInTopology(
ctx context.Context, eventID string,
) (depth types.StreamPosition, stream types.StreamPosition, err error) {
return d.Topology.SelectPositionInTopology(ctx, nil, eventID)
) (types.TopologyToken, error) {
depth, stream, err := d.Topology.SelectPositionInTopology(ctx, nil, eventID)
if err != nil {
return types.NewTopologyToken(0, 0), err
}
return types.NewTopologyToken(depth, stream), nil
}
// TODO FIXME TEMPORARY PUBLIC
func (d *Database) SyncPositionTx(
func (d *Database) syncPositionTx(
ctx context.Context, txn *sql.Tx,
) (sp types.StreamingToken, err error) {
@ -466,7 +462,7 @@ func (d *Database) addPDUDeltaToResponse(
}
// 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, fromPos, toPos, res); err != nil {
return nil, err
}
@ -510,8 +506,7 @@ func (d *Database) addTypingDeltaToResponse(
// addEDUDeltaToResponse adds updates for EDUs of each type since fromPos if
// the positions of that type are not equal in fromPos and toPos.
// TODO FIXME TEMPORARY PUBLIC
func (d *Database) AddEDUDeltaToResponse(
func (d *Database) addEDUDeltaToResponse(
fromPos, toPos types.StreamingToken,
joinedRoomIDs []string,
res *types.Response,
@ -551,7 +546,7 @@ func (d *Database) IncrementalSync(
return nil, err
}
err = d.AddEDUDeltaToResponse(
err = d.addEDUDeltaToResponse(
fromPos, toPos, joinedRoomIDs, res,
)
if err != nil {
@ -590,7 +585,7 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
}()
// Get the current sync position which we will base the sync response on.
toPos, err = d.SyncPositionTx(ctx, txn)
toPos, err = d.syncPositionTx(ctx, txn)
if err != nil {
return
}
@ -649,7 +644,7 @@ 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, 0, toPos.PDUPosition(), res); err != nil {
return
}
@ -668,7 +663,7 @@ func (d *Database) CompleteSync(
}
// Use a zero value SyncPosition for fromPos so all EDU states are added.
err = d.AddEDUDeltaToResponse(
err = d.addEDUDeltaToResponse(
types.NewStreamToken(0, 0), toPos, joinedRoomIDs, res,
)
if err != nil {
@ -688,8 +683,7 @@ var txReadOnlySnapshot = sql.TxOptions{
ReadOnly: true,
}
// TODO FIXME temporary public
func (d *Database) AddInvitesToResponse(
func (d *Database) addInvitesToResponse(
ctx context.Context, txn *sql.Tx,
userID string,
fromPos, toPos types.StreamPosition,

5
syncapi/storage/sqlite3/output_room_events_table.go
View file

@ -306,9 +306,6 @@ func (s *outputRoomEventsStatements) InsertEvent(
return
}
// selectRecentEvents returns the most recent events in the given room, up to a maximum of 'limit'.
// If onlySyncEvents has a value of true, only returns the events that aren't marked as to exclude
// from sync.
func (s *outputRoomEventsStatements) SelectRecentEvents(
ctx context.Context, txn *sql.Tx,
roomID string, fromPos, toPos types.StreamPosition, limit int,
@ -341,8 +338,6 @@ func (s *outputRoomEventsStatements) SelectRecentEvents(
return events, nil
}
// selectEarlyEvents returns the earliest events in the given room, starting
// 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,

40
syncapi/storage/sqlite3/output_room_events_topology_table.go
View file

@ -65,17 +65,12 @@ const selectMaxPositionInTopologySQL = "" +
"SELECT MAX(topological_position), stream_position FROM syncapi_output_room_events_topology" +
" WHERE room_id = $1 ORDER BY stream_position DESC"
const selectEventIDsFromPositionSQL = "" +
"SELECT event_id FROM syncapi_output_room_events_topology" +
" WHERE room_id = $1 AND topological_position = $2"
type outputRoomEventsTopologyStatements struct {
insertEventInTopologyStmt *sql.Stmt
selectEventIDsInRangeASCStmt *sql.Stmt
selectEventIDsInRangeDESCStmt *sql.Stmt
selectPositionInTopologyStmt *sql.Stmt
selectMaxPositionInTopologyStmt *sql.Stmt
selectEventIDsFromPositionStmt *sql.Stmt
}
func NewSqliteTopologyTable(db *sql.DB) (tables.Topology, error) {
@ -99,9 +94,6 @@ func NewSqliteTopologyTable(db *sql.DB) (tables.Topology, error) {
if s.selectMaxPositionInTopologyStmt, err = db.Prepare(selectMaxPositionInTopologySQL); err != nil {
return nil, err
}
if s.selectEventIDsFromPositionStmt, err = db.Prepare(selectEventIDsFromPositionSQL); err != nil {
return nil, err
}
return s, nil
}
@ -117,12 +109,9 @@ func (s *outputRoomEventsTopologyStatements) InsertEventInTopology(
return
}
// selectEventIDsInRange selects the IDs of events which positions are within a
// given range in a given room's topological order.
// Returns an empty slice if no events match the given range.
func (s *outputRoomEventsTopologyStatements) SelectEventIDsInRange(
ctx context.Context, txn *sql.Tx, roomID string,
fromPos, toPos, toMicroPos types.StreamPosition,
minDepth, maxDepth, maxStreamPos types.StreamPosition,
limit int, chronologicalOrder bool,
) (eventIDs []string, err error) {
// Decide on the selection's order according to whether chronological order
@ -135,7 +124,7 @@ func (s *outputRoomEventsTopologyStatements) SelectEventIDsInRange(
}
// Query the event IDs.
rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, toPos, toMicroPos, limit)
rows, err := stmt.QueryContext(ctx, roomID, minDepth, maxDepth, maxDepth, maxStreamPos, limit)
if err == sql.ErrNoRows {
// If no event matched the request, return an empty slice.
return []string{}, nil
@ -172,28 +161,3 @@ func (s *outputRoomEventsTopologyStatements) SelectMaxPositionInTopology(
err = stmt.QueryRowContext(ctx, roomID).Scan(&pos, &spos)
return
}
// selectEventIDsFromPosition returns the IDs of all events that have a given
// position in the topology of a given room.
func (s *outputRoomEventsTopologyStatements) SelectEventIDsFromPosition(
ctx context.Context, txn *sql.Tx, roomID string, pos types.StreamPosition,
) (eventIDs []string, err error) {
// Query the event IDs.
stmt := common.TxStmt(txn, s.selectEventIDsFromPositionStmt)
rows, err := stmt.QueryContext(ctx, roomID, pos)
if err == sql.ErrNoRows {
// If no event matched the request, return an empty slice.
return []string{}, nil
} else if err != nil {
return
}
// Return the IDs.
var eventID string
for rows.Next() {
if err = rows.Scan(&eventID); err != nil {
return
}
eventIDs = append(eventIDs, eventID)
}
return
}

13
syncapi/storage/storage_test.go
View file

@ -292,11 +292,10 @@ func TestGetEventsInRangeWithTopologyToken(t *testing.T) {
db := MustCreateDatabase(t)
events, _ := SimpleRoom(t, testRoomID, testUserIDA, testUserIDB)
MustWriteEvents(t, db, events)
latest, latestStream, err := db.MaxTopologicalPosition(ctx, testRoomID)
from, err := db.MaxTopologicalPosition(ctx, testRoomID)
if err != nil {
t.Fatalf("failed to get MaxTopologicalPosition: %s", err)
}
from := types.NewTopologyToken(latest, latestStream)
// head towards the beginning of time
to := types.NewTopologyToken(0, 0)
@ -358,16 +357,14 @@ func TestGetEventsInRangeWithEventsSameDepth(t *testing.T) {
Depth: depth + 1,
}))
MustWriteEvents(t, db, events)
latestPos, latestStreamPos, err := db.EventPositionInTopology(ctx, events[len(events)-1].EventID())
fromLatest, err := db.EventPositionInTopology(ctx, events[len(events)-1].EventID())
if err != nil {
t.Fatalf("failed to get EventPositionInTopology: %s", err)
}
topoPos, streamPos, err := db.EventPositionInTopology(ctx, events[len(events)-3].EventID()) // Message 2
fromFork, err := db.EventPositionInTopology(ctx, events[len(events)-3].EventID()) // Message 2
if err != nil {
t.Fatalf("failed to get EventPositionInTopology for event: %s", err)
}
fromLatest := types.NewTopologyToken(latestPos, latestStreamPos)
fromFork := types.NewTopologyToken(topoPos, streamPos)
// head towards the beginning of time
to := types.NewTopologyToken(0, 0)
@ -507,12 +504,10 @@ func assertEventsEqual(t *testing.T, msg string, checkRoomID bool, gots []gomatr
}
func topologyTokenBefore(t *testing.T, db storage.Database, eventID string) *types.TopologyToken {
pos, spos, err := db.EventPositionInTopology(ctx, eventID)
tok, err := db.EventPositionInTopology(ctx, eventID)
if err != nil {
t.Fatalf("failed to get EventPositionInTopology: %s", err)
}
tok := types.NewTopologyToken(pos, spos)
tok.Decrement()
return &tok
}

32
syncapi/storage/tables/interface.go
View file

@ -11,13 +11,15 @@ import (
type AccountData interface {
InsertAccountData(ctx context.Context, txn *sql.Tx, userID, roomID, dataType string) (pos types.StreamPosition, err error)
SelectAccountDataInRange(ctx context.Context, userID string, oldPos, newPos types.StreamPosition, accountDataEventFilter *gomatrixserverlib.EventFilter) (data map[string][]string, 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(ctx context.Context, userID string, lowPos, hiPos types.StreamPosition, 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(ctx context.Context, txn *sql.Tx, targetUserID string, startPos, endPos types.StreamPosition) (map[string]gomatrixserverlib.HeaderedEvent, error)
SelectMaxInviteID(ctx context.Context, txn *sql.Tx) (id int64, err error)
}
@ -26,26 +28,30 @@ 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)
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`.
// 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)
// SelectEarlyEvents returns the earliest events in the given room, exclusive of `fromPos` and inclusive of `toPos`.
SelectEarlyEvents(ctx context.Context, txn *sql.Tx, roomID string, fromPos, toPos types.StreamPosition, limit int) ([]types.StreamEvent, error)
SelectEvents(ctx context.Context, txn *sql.Tx, eventIDs []string) ([]types.StreamEvent, error)
}
// Topology keeps track of the depths and stream positions for all events.
// These positions are used as types.TopologyToken when backfilling events locally.
type Topology interface {
// InsertEventInTopology inserts the given event in the room's topology, based
// on the event's depth.
// InsertEventInTopology inserts the given event in the room's topology, based on the event's depth.
// `pos` is the stream position of this event in the events table, and is used to order events which have the same depth.
InsertEventInTopology(ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent, pos types.StreamPosition) (err error)
// SelectEventIDsInRange selects the IDs of events which positions are within a
// given range in a given room's topological order.
// SelectEventIDsInRange selects the IDs of events whose depths are within a given range in a given room's topological order.
// Events with `minDepth` are *exclusive*, as is the event which has exactly `minDepth`,`maxStreamPos`.
// `maxStreamPos` is only used when events have the same depth as `maxDepth`, which results in events less than `maxStreamPos` being returned.
// Returns an empty slice if no events match the given range.
SelectEventIDsInRange(ctx context.Context, txn *sql.Tx, roomID string, fromPos, toPos, toMicroPos types.StreamPosition, limit int, chronologicalOrder bool) (eventIDs []string, err error)
// SelectPositionInTopology returns the position of a given event in the
// topology of the room it belongs to.
SelectPositionInTopology(ctx context.Context, txn *sql.Tx, eventID string) (pos, spos types.StreamPosition, err error)
SelectMaxPositionInTopology(ctx context.Context, txn *sql.Tx, roomID string) (pos types.StreamPosition, spos types.StreamPosition, err error)
// SelectEventIDsFromPosition returns the IDs of all events that have a given
// position in the topology of a given room.
SelectEventIDsFromPosition(ctx context.Context, txn *sql.Tx, roomID string, pos types.StreamPosition) (eventIDs []string, err error)
SelectEventIDsInRange(ctx context.Context, txn *sql.Tx, roomID string, minDepth, maxDepth, maxStreamPos types.StreamPosition, limit int, chronologicalOrder bool) (eventIDs []string, err error)
// SelectPositionInTopology returns the depth and stream position of a given event in the topology of the room it belongs to.
SelectPositionInTopology(ctx context.Context, txn *sql.Tx, eventID string) (depth, spos types.StreamPosition, err error)
// SelectMaxPositionInTopology returns the event which has the highest depth, and if there are multiple, the event with the highest stream position.
SelectMaxPositionInTopology(ctx context.Context, txn *sql.Tx, roomID string) (depth types.StreamPosition, spos types.StreamPosition, err error)
}
type CurrentRoomState interface {

3
syncapi/types/types.go
View file

@ -119,8 +119,11 @@ func (t *TopologyToken) Decrement() {
depth := t.Positions[0]
pduPos := t.Positions[1]
if depth-1 <= 0 {
// nothing can be lower than this
depth = 1
} else {
// this assumes that we will never have 1000 events all with the same
// depth. TODO: work out what the right PDU position is to use, probably needs a db hit.
depth--
pduPos += 1000
}