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Reduce memory usage in federation /send endpoint (#1890) 

* More aggressive event caching

* Deduplicate /state results

* Deduplicate more

* Ensure we use the correct list of events when excluding repeated state

* Fixes

* Ensure we track all events we already knew about properly
main
Neil Alexander 2021-06-30 10:01:56 +01:00 committed by GitHub
parent c849e74dfc
commit 3afb161352
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 41 additions and 30 deletions
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69
federationapi/routing/send.go
View File

@ -106,8 +106,8 @@ func Send(
eduAPI: eduAPI,
keys: keys,
federation: federation,
hadEvents: make(map[string]bool),
haveEvents: make(map[string]*gomatrixserverlib.HeaderedEvent),
newEvents: make(map[string]bool),
keyAPI: keyAPI,
roomsMu: mu,
}
@ -167,13 +167,12 @@ type txnReq struct {
servers []gomatrixserverlib.ServerName
serversMutex sync.RWMutex
roomsMu *internal.MutexByRoom
// a list of events from the auth and prev events which we already had
hadEvents map[string]bool
// local cache of events for auth checks, etc - this may include events
// which the roomserver is unaware of.
haveEvents map[string]*gomatrixserverlib.HeaderedEvent
// new events which the roomserver does not know about
newEvents map[string]bool
newEventsMutex sync.RWMutex
work string // metrics
work string // metrics
}
// A subset of FederationClient functionality that txn requires. Useful for testing.
@ -340,19 +339,6 @@ func (e missingPrevEventsError) Error() string {
return fmt.Sprintf("unable to get prev_events for event %q: %s", e.eventID, e.err)
}
func (t *txnReq) haveEventIDs() map[string]bool {
t.newEventsMutex.RLock()
defer t.newEventsMutex.RUnlock()
result := make(map[string]bool, len(t.haveEvents))
for eventID := range t.haveEvents {
if t.newEvents[eventID] {
continue
}
result[eventID] = true
}
return result
}
func (t *txnReq) processEDUs(ctx context.Context) {
for _, e := range t.EDUs {
eduCountTotal.Inc()
@ -527,6 +513,15 @@ func (t *txnReq) processEvent(ctx context.Context, e *gomatrixserverlib.Event) e
return roomNotFoundError{e.RoomID()}
}
// Prepare a map of all the events we already had before this point, so
// that we don't send them to the roomserver again.
for _, eventID := range append(e.AuthEventIDs(), e.PrevEventIDs()...) {
t.hadEvents[eventID] = true
}
for _, eventID := range append(stateResp.MissingAuthEventIDs, stateResp.MissingPrevEventIDs...) {
t.hadEvents[eventID] = false
}
if len(stateResp.MissingAuthEventIDs) > 0 {
t.work = MetricsWorkMissingAuthEvents
logger.Infof("Event refers to %d unknown auth_events", len(stateResp.MissingAuthEventIDs))
@ -596,6 +591,8 @@ withNextEvent:
); err != nil {
return fmt.Errorf("api.SendEvents: %w", err)
}
t.hadEvents[ev.EventID()] = true // if the roomserver didn't know about the event before, it does now
t.cacheAndReturn(ev.Headered(stateResp.RoomVersion))
delete(missingAuthEvents, missingAuthEventID)
continue withNextEvent
}
@ -739,7 +736,7 @@ func (t *txnReq) processEventWithMissingState(
api.KindOld,
resolvedState,
backwardsExtremity.Headered(roomVersion),
t.haveEventIDs(),
t.hadEvents,
)
if err != nil {
return fmt.Errorf("api.SendEventWithState: %w", err)
@ -791,7 +788,7 @@ func (t *txnReq) lookupStateAfterEvent(ctx context.Context, roomVersion gomatrix
default:
return nil, false, fmt.Errorf("t.lookupEvent: %w", err)
}
t.cacheAndReturn(h)
h = t.cacheAndReturn(h)
if h.StateKey() != nil {
addedToState := false
for i := range respState.StateEvents {
@ -833,6 +830,7 @@ func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, event
// set the event from the haveEvents cache - this means we will share pointers with other prev_event branches for this
// processEvent request, which is better for memory.
stateEvents[i] = t.cacheAndReturn(ev)
t.hadEvents[ev.EventID()] = true
}
// we should never access res.StateEvents again so we delete it here to make GC faster
res.StateEvents = nil
@ -863,8 +861,9 @@ func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, event
if err = t.rsAPI.QueryEventsByID(ctx, &queryReq, &queryRes); err != nil {
return nil
}
for i := range queryRes.Events {
for i, ev := range queryRes.Events {
authEvents = append(authEvents, t.cacheAndReturn(queryRes.Events[i]).Unwrap())
t.hadEvents[ev.EventID()] = true
}
queryRes.Events = nil
}
@ -939,8 +938,9 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e *gomatrixserverlib.Even
return nil, err
}
latestEvents := make([]string, len(res.LatestEvents))
for i := range res.LatestEvents {
for i, ev := range res.LatestEvents {
latestEvents[i] = res.LatestEvents[i].EventID
t.hadEvents[ev.EventID] = true
}
var missingResp *gomatrixserverlib.RespMissingEvents
@ -985,6 +985,12 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e *gomatrixserverlib.Even
// For now, we do not allow Case B, so reject the event.
logger.Infof("get_missing_events returned %d events", len(missingResp.Events))
// Make sure events from the missingResp are using the cache - missing events
// will be added and duplicates will be removed.
for i, ev := range missingResp.Events {
missingResp.Events[i] = t.cacheAndReturn(ev.Headered(roomVersion)).Unwrap()
}
// topologically sort and sanity check that we are making forward progress
newEvents = gomatrixserverlib.ReverseTopologicalOrdering(missingResp.Events, gomatrixserverlib.TopologicalOrderByPrevEvents)
shouldHaveSomeEventIDs := e.PrevEventIDs()
@ -1023,6 +1029,14 @@ func (t *txnReq) lookupMissingStateViaState(ctx context.Context, roomID, eventID
if err := state.Check(ctx, t.keys, nil); err != nil {
return nil, err
}
// Cache the results of this state lookup and deduplicate anything we already
// have in the cache, freeing up memory.
for i, ev := range state.AuthEvents {
state.AuthEvents[i] = t.cacheAndReturn(ev.Headered(roomVersion)).Unwrap()
}
for i, ev := range state.StateEvents {
state.StateEvents[i] = t.cacheAndReturn(ev.Headered(roomVersion)).Unwrap()
}
return &state, nil
}
@ -1055,9 +1069,10 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
if err = t.rsAPI.QueryEventsByID(ctx, &queryReq, &queryRes); err != nil {
return nil, err
}
for i := range queryRes.Events {
for i, ev := range queryRes.Events {
queryRes.Events[i] = t.cacheAndReturn(queryRes.Events[i])
t.hadEvents[ev.EventID()] = true
evID := queryRes.Events[i].EventID()
t.cacheAndReturn(queryRes.Events[i])
if missing[evID] {
delete(missing, evID)
}
@ -1221,9 +1236,5 @@ func (t *txnReq) lookupEvent(ctx context.Context, roomVersion gomatrixserverlib.
util.GetLogger(ctx).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
return nil, verifySigError{event.EventID(), err}
}
h := event.Headered(roomVersion)
t.newEventsMutex.Lock()
t.newEvents[h.EventID()] = true
t.newEventsMutex.Unlock()
return h, nil
return t.cacheAndReturn(event.Headered(roomVersion)), nil
}

2
federationapi/routing/send_test.go
View File

@ -370,7 +370,7 @@ func mustCreateTransaction(rsAPI api.RoomserverInternalAPI, fedClient txnFederat
keys: &test.NopJSONVerifier{},
federation: fedClient,
haveEvents: make(map[string]*gomatrixserverlib.HeaderedEvent),
newEvents: make(map[string]bool),
hadEvents: make(map[string]bool),
roomsMu: internal.NewMutexByRoom(),
}
t.PDUs = pdus