From 688129fbcb2999a055f8d536151871e0d83ced22 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Mon, 2 Oct 2023 16:58:41 +0200
Subject: [PATCH] Tweaks around the device list updater

---
 userapi/internal/device_list_update.go | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/userapi/internal/device_list_update.go b/userapi/internal/device_list_update.go
index 64b437bf7..a8d347eac 100644
--- a/userapi/internal/device_list_update.go
+++ b/userapi/internal/device_list_update.go
@@ -180,11 +180,27 @@ func (u *DeviceListUpdater) Start() error {
 	if err != nil {
 		return err
 	}
+
+	// Filter out dupe domains, as processServer is going to get all users anyway
+	seenDomains := make(map[spec.ServerName]struct{})
+	newStateLists := make([]string, 0, len(staleLists))
+	for _, userID := range staleLists {
+		_, domain, err := gomatrixserverlib.SplitID('@', userID)
+		if err != nil {
+			// non-fatal and should not block starting up
+			continue
+		}
+		if _, ok := seenDomains[domain]; ok {
+			continue
+		}
+		newStateLists = append(newStateLists, userID)
+		seenDomains[domain] = struct{}{}
+	}
 	offset, step := time.Second*10, time.Second
-	if max := len(staleLists); max > 120 {
+	if max := len(newStateLists); max > 120 {
 		step = (time.Second * 120) / time.Duration(max)
 	}
-	for _, userID := range staleLists {
+	for _, userID := range newStateLists {
 		userID := userID // otherwise we are only sending the last entry
 		time.AfterFunc(offset, func() {
 			u.notifyWorkers(userID)
@@ -467,6 +483,11 @@ func (u *DeviceListUpdater) processServer(serverName spec.ServerName) (time.Dura
 func (u *DeviceListUpdater) processServerUser(ctx context.Context, serverName spec.ServerName, userID string) (time.Duration, error) {
 	ctx, cancel := context.WithTimeout(ctx, requestTimeout)
 	defer cancel()
+
+	// If we are processing more than one user per server, this unblocks further calls to Update
+	// immediately instead of just after **all** users have been processed.
+	defer u.clearChannel(userID)
+
 	logger := util.GetLogger(ctx).WithFields(logrus.Fields{
 		"server_name": serverName,
 		"user_id":     userID,