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
This commit is contained in:
Neil Alexander 2022-02-24 11:09:01 +00:00 committed by GitHub
parent fea8d152e7
commit 4b01f1cd12
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@ -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.
@ -850,8 +851,21 @@ 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.
@ -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