perf: batch group unread fanout

server/pres.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/tinode/chat/server/logs"
+	immetrics "github.com/tinode/chat/server/metrics"
 	"github.com/tinode/chat/server/store"
 	"github.com/tinode/chat/server/store/types"
 )
@@ -466,12 +467,26 @@ func (t *Topic) presSubsOffline(what string, params *presParams,
 	if offlineOnly {
 		skipTopic = t.name
 	}
+	if t.cat == types.TopicCatGrp && offlineOnly && what == "msg" && store.RealtimeFanoutEnabled() {
+		recipients := make([]realtimeGroupUnreadRecipient, 0, len(t.perUser))
+		for uid, pud := range t.perUser {
+			if pud.deleted || !presOfflineFilter(pud.modeGiven&pud.modeWant, what, filterSource) {
+				continue
+			}
+			recipients = append(recipients, realtimeGroupUnreadRecipient{
+				User:   uid.UserId(),
+				Source: t.original(uid),
+			})
+		}
+		if publishRealtimeGroupUnread(t.tenantID, t.name, params.actor, params.seqID, recipients) {
+			return
+		}
+	}
 
 	for uid, pud := range t.perUser {
 		if pud.deleted || !presOfflineFilter(pud.modeGiven&pud.modeWant, what, filterSource) {
 			continue
 		}
-
 		user := uid.UserId()
 		actor := params.actor
 		target := params.target
@@ -693,10 +708,16 @@ func presSingleUserOfflineOffline(tenantID types.TenantID, uid types.Uid, origin
 }
 
 func routeUserServerMessage(uid types.Uid, msg *ServerComMessage) {
-	if msg == nil || uid.IsZero() {
+	if msg == nil || uid.IsZero() || globals.hub == nil {
 		return
 	}
-	globals.hub.routeSrv <- msg
+	select {
+	case globals.hub.routeSrv <- msg:
+		immetrics.ObserveInternalQueueEnqueue("hub_route_server", len(globals.hub.routeSrv), cap(globals.hub.routeSrv), true)
+	default:
+		immetrics.ObserveInternalQueueEnqueue("hub_route_server", len(globals.hub.routeSrv), cap(globals.hub.routeSrv), false)
+		logs.Err.Printf("route user message: hub routeSrv queue full, user=%s", uid.UserId())
+	}
 	publishRealtimeUserMessage(uid, msg)
 }