From 4b01f1cd122ed155ff8b05aa848f4daf2aa60c34 Mon Sep 17 00:00:00 2001 From: Neil Alexander Date: Thu, 24 Feb 2022 11:09:01 +0000 Subject: State resolution v2 micro-optimisations (#2226) * Don't populate duplicates into auth events * Only append the single event * Potentially reduce number of iterations in `isInAllAuthLists --- roomserver/state/state.go | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'roomserver') diff --git a/roomserver/state/state.go b/roomserver/state/state.go index e5f69521..187b996c 100644 --- a/roomserver/state/state.go +++ b/roomserver/state/state.go @@ -814,6 +814,7 @@ func (v *StateResolution) resolveConflictsV2( // events may be duplicated across these sets but that's OK. authSets := make(map[string][]*gomatrixserverlib.Event, len(conflicted)) authEvents := make([]*gomatrixserverlib.Event, 0, estimate*3) + gotAuthEvents := make(map[string]struct{}, estimate*3) authDifference := make([]*gomatrixserverlib.Event, 0, estimate) // For each conflicted event, let's try and get the needed auth events. @@ -850,9 +851,22 @@ func (v *StateResolution) resolveConflictsV2( if err != nil { return nil, err } - authEvents = append(authEvents, authSets[key]...) + + // Only add auth events into the authEvents slice once, otherwise the + // check for the auth difference can become expensive and produce + // duplicate entries, which just waste memory and CPU time. + for _, event := range authSets[key] { + if _, ok := gotAuthEvents[event.EventID()]; !ok { + authEvents = append(authEvents, event) + gotAuthEvents[event.EventID()] = struct{}{} + } + } } + // Kill the reference to this so that the GC may pick it up, since we no + // longer need this after this point. + gotAuthEvents = nil // nolint:ineffassign + // This function helps us to work out whether an event exists in one of the // auth sets. isInAuthList := func(k string, event *gomatrixserverlib.Event) bool { @@ -866,11 +880,12 @@ func (v *StateResolution) resolveConflictsV2( // This function works out if an event exists in all of the auth sets. isInAllAuthLists := func(event *gomatrixserverlib.Event) bool { - found := true for k := range authSets { - found = found && isInAuthList(k, event) + if !isInAuthList(k, event) { + return false + } } - return found + return true } // Look through all of the auth events that we've been given and work out if -- cgit v1.2.3